diff options
Diffstat (limited to 'src/expr.rs')
| -rw-r--r-- | src/expr.rs | 2930 |
1 files changed, 0 insertions, 2930 deletions
diff --git a/src/expr.rs b/src/expr.rs deleted file mode 100644 index fb873ee26d3..00000000000 --- a/src/expr.rs +++ /dev/null @@ -1,2930 +0,0 @@ -// Copyright 2015 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -use std::borrow::Cow; -use std::cmp::min; -use std::iter::repeat; - -use syntax::{ast, ptr}; -use syntax::codemap::{BytePos, CodeMap, Span}; - -use chains::rewrite_chain; -use closures; -use codemap::{LineRangeUtils, SpanUtils}; -use comment::{combine_strs_with_missing_comments, contains_comment, recover_comment_removed, - rewrite_comment, rewrite_missing_comment, FindUncommented}; -use config::{Config, ControlBraceStyle, IndentStyle}; -use lists::{definitive_tactic, itemize_list, shape_for_tactic, struct_lit_formatting, - struct_lit_shape, struct_lit_tactic, write_list, DefinitiveListTactic, ListFormatting, - ListItem, ListTactic, Separator, SeparatorPlace, SeparatorTactic}; -use macros::{rewrite_macro, MacroArg, MacroPosition}; -use patterns::{can_be_overflowed_pat, TuplePatField}; -use rewrite::{Rewrite, RewriteContext}; -use shape::{Indent, Shape}; -use spanned::Spanned; -use string::{rewrite_string, StringFormat}; -use types::{can_be_overflowed_type, rewrite_path, PathContext}; -use utils::{colon_spaces, contains_skip, count_newlines, extra_offset, first_line_width, - inner_attributes, last_line_extendable, last_line_width, mk_sp, outer_attributes, - paren_overhead, ptr_vec_to_ref_vec, semicolon_for_stmt, trimmed_last_line_width, - wrap_str}; -use vertical::rewrite_with_alignment; -use visitor::FmtVisitor; - -impl Rewrite for ast::Expr { - fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> { - format_expr(self, ExprType::SubExpression, context, shape) - } -} - -#[derive(Copy, Clone, PartialEq)] -pub enum ExprType { - Statement, - SubExpression, -} - -pub fn format_expr( - expr: &ast::Expr, - expr_type: ExprType, - context: &RewriteContext, - shape: Shape, -) -> Option<String> { - skip_out_of_file_lines_range!(context, expr.span); - - if contains_skip(&*expr.attrs) { - return Some(context.snippet(expr.span()).to_owned()); - } - - let expr_rw = match expr.node { - ast::ExprKind::Array(ref expr_vec) => rewrite_array( - &ptr_vec_to_ref_vec(expr_vec), - mk_sp(context.codemap.span_after(expr.span, "["), expr.span.hi()), - context, - shape, - false, - ), - ast::ExprKind::Lit(ref l) => rewrite_literal(context, l, shape), - ast::ExprKind::Call(ref callee, ref args) => { - let inner_span = mk_sp(callee.span.hi(), expr.span.hi()); - let callee_str = callee.rewrite(context, shape)?; - rewrite_call(context, &callee_str, args, inner_span, shape) - } - ast::ExprKind::Paren(ref subexpr) => rewrite_paren(context, subexpr, shape), - ast::ExprKind::Binary(ref op, ref lhs, ref rhs) => { - // FIXME: format comments between operands and operator - rewrite_pair( - &**lhs, - &**rhs, - PairParts::new("", &format!(" {} ", context.snippet(op.span)), ""), - context, - shape, - context.config.binop_separator(), - ) - } - ast::ExprKind::Unary(ref op, ref subexpr) => rewrite_unary_op(context, op, subexpr, shape), - ast::ExprKind::Struct(ref path, ref fields, ref base) => rewrite_struct_lit( - context, - path, - fields, - base.as_ref().map(|e| &**e), - expr.span, - shape, - ), - ast::ExprKind::Tup(ref items) => { - rewrite_tuple(context, &ptr_vec_to_ref_vec(items), expr.span, shape) - } - ast::ExprKind::If(..) - | ast::ExprKind::IfLet(..) - | ast::ExprKind::ForLoop(..) - | ast::ExprKind::Loop(..) - | ast::ExprKind::While(..) - | ast::ExprKind::WhileLet(..) => to_control_flow(expr, expr_type) - .and_then(|control_flow| control_flow.rewrite(context, shape)), - ast::ExprKind::Block(ref block) => { - match expr_type { - ExprType::Statement => { - if is_unsafe_block(block) { - block.rewrite(context, shape) - } else if let rw @ Some(_) = rewrite_empty_block(context, block, shape) { - // Rewrite block without trying to put it in a single line. - rw - } else { - let prefix = block_prefix(context, block, shape)?; - rewrite_block_with_visitor(context, &prefix, block, shape, true) - } - } - ExprType::SubExpression => block.rewrite(context, shape), - } - } - ast::ExprKind::Match(ref cond, ref arms) => { - rewrite_match(context, cond, arms, shape, expr.span, &expr.attrs) - } - ast::ExprKind::Path(ref qself, ref path) => { - rewrite_path(context, PathContext::Expr, qself.as_ref(), path, shape) - } - ast::ExprKind::Assign(ref lhs, ref rhs) => { - rewrite_assignment(context, lhs, rhs, None, shape) - } - ast::ExprKind::AssignOp(ref op, ref lhs, ref rhs) => { - rewrite_assignment(context, lhs, rhs, Some(op), shape) - } - ast::ExprKind::Continue(ref opt_label) => { - let id_str = match *opt_label { - Some(label) => format!(" {}", label.ident), - None => String::new(), - }; - Some(format!("continue{}", id_str)) - } - ast::ExprKind::Break(ref opt_label, ref opt_expr) => { - let id_str = match *opt_label { - Some(label) => format!(" {}", label.ident), - None => String::new(), - }; - - if let Some(ref expr) = *opt_expr { - rewrite_unary_prefix(context, &format!("break{} ", id_str), &**expr, shape) - } else { - Some(format!("break{}", id_str)) - } - } - ast::ExprKind::Yield(ref opt_expr) => if let Some(ref expr) = *opt_expr { - rewrite_unary_prefix(context, "yield ", &**expr, shape) - } else { - Some("yield".to_string()) - }, - ast::ExprKind::Closure(capture, movability, ref fn_decl, ref body, _) => { - closures::rewrite_closure( - capture, - movability, - fn_decl, - body, - expr.span, - context, - shape, - ) - } - ast::ExprKind::Try(..) - | ast::ExprKind::Field(..) - | ast::ExprKind::TupField(..) - | ast::ExprKind::MethodCall(..) => rewrite_chain(expr, context, shape), - ast::ExprKind::Mac(ref mac) => { - rewrite_macro(mac, None, context, shape, MacroPosition::Expression).or_else(|| { - wrap_str( - context.snippet(expr.span).to_owned(), - context.config.max_width(), - shape, - ) - }) - } - ast::ExprKind::Ret(None) => Some("return".to_owned()), - ast::ExprKind::Ret(Some(ref expr)) => { - rewrite_unary_prefix(context, "return ", &**expr, shape) - } - ast::ExprKind::Box(ref expr) => rewrite_unary_prefix(context, "box ", &**expr, shape), - ast::ExprKind::AddrOf(mutability, ref expr) => { - rewrite_expr_addrof(context, mutability, expr, shape) - } - ast::ExprKind::Cast(ref expr, ref ty) => rewrite_pair( - &**expr, - &**ty, - PairParts::new("", " as ", ""), - context, - shape, - SeparatorPlace::Front, - ), - ast::ExprKind::Type(ref expr, ref ty) => rewrite_pair( - &**expr, - &**ty, - PairParts::new("", ": ", ""), - context, - shape, - SeparatorPlace::Back, - ), - ast::ExprKind::Index(ref expr, ref index) => { - rewrite_index(&**expr, &**index, context, shape) - } - ast::ExprKind::Repeat(ref expr, ref repeats) => { - let (lbr, rbr) = if context.config.spaces_within_parens_and_brackets() { - ("[ ", " ]") - } else { - ("[", "]") - }; - rewrite_pair( - &**expr, - &**repeats, - PairParts::new(lbr, "; ", rbr), - context, - shape, - SeparatorPlace::Back, - ) - } - ast::ExprKind::Range(ref lhs, ref rhs, limits) => { - let delim = match limits { - ast::RangeLimits::HalfOpen => "..", - ast::RangeLimits::Closed => "..=", - }; - - fn needs_space_before_range(context: &RewriteContext, lhs: &ast::Expr) -> bool { - match lhs.node { - ast::ExprKind::Lit(ref lit) => match lit.node { - ast::LitKind::FloatUnsuffixed(..) => { - context.snippet(lit.span).ends_with('.') - } - _ => false, - }, - _ => false, - } - } - - match (lhs.as_ref().map(|x| &**x), rhs.as_ref().map(|x| &**x)) { - (Some(lhs), Some(rhs)) => { - let sp_delim = if context.config.spaces_around_ranges() { - format!(" {} ", delim) - } else if needs_space_before_range(context, lhs) { - format!(" {}", delim) - } else { - delim.to_owned() - }; - rewrite_pair( - &*lhs, - &*rhs, - PairParts::new("", &sp_delim, ""), - context, - shape, - context.config.binop_separator(), - ) - } - (None, Some(rhs)) => { - let sp_delim = if context.config.spaces_around_ranges() { - format!("{} ", delim) - } else { - delim.to_owned() - }; - rewrite_unary_prefix(context, &sp_delim, &*rhs, shape) - } - (Some(lhs), None) => { - let sp_delim = if context.config.spaces_around_ranges() { - format!(" {}", delim) - } else { - delim.to_owned() - }; - rewrite_unary_suffix(context, &sp_delim, &*lhs, shape) - } - (None, None) => Some(delim.to_owned()), - } - } - // We do not format these expressions yet, but they should still - // satisfy our width restrictions. - ast::ExprKind::InPlace(..) | ast::ExprKind::InlineAsm(..) => { - Some(context.snippet(expr.span).to_owned()) - } - ast::ExprKind::Catch(ref block) => { - if let rw @ Some(_) = rewrite_single_line_block(context, "do catch ", block, shape) { - rw - } else { - // 9 = `do catch ` - let budget = shape.width.checked_sub(9).unwrap_or(0); - Some(format!( - "{}{}", - "do catch ", - block.rewrite(context, Shape::legacy(budget, shape.indent))? - )) - } - } - }; - - expr_rw - .and_then(|expr_str| recover_comment_removed(expr_str, expr.span, context)) - .and_then(|expr_str| { - let attrs = outer_attributes(&expr.attrs); - let attrs_str = attrs.rewrite(context, shape)?; - let span = mk_sp( - attrs.last().map_or(expr.span.lo(), |attr| attr.span.hi()), - expr.span.lo(), - ); - combine_strs_with_missing_comments(context, &attrs_str, &expr_str, span, shape, false) - }) -} - -#[derive(new, Clone, Copy)] -pub struct PairParts<'a> { - prefix: &'a str, - infix: &'a str, - suffix: &'a str, -} - -pub fn rewrite_pair<LHS, RHS>( - lhs: &LHS, - rhs: &RHS, - pp: PairParts, - context: &RewriteContext, - shape: Shape, - separator_place: SeparatorPlace, -) -> Option<String> -where - LHS: Rewrite, - RHS: Rewrite, -{ - let lhs_overhead = match separator_place { - SeparatorPlace::Back => shape.used_width() + pp.prefix.len() + pp.infix.trim_right().len(), - SeparatorPlace::Front => shape.used_width(), - }; - let lhs_shape = Shape { - width: context.budget(lhs_overhead), - ..shape - }; - let lhs_result = lhs.rewrite(context, lhs_shape) - .map(|lhs_str| format!("{}{}", pp.prefix, lhs_str))?; - - // Try to the both lhs and rhs on the same line. - let rhs_orig_result = shape - .offset_left(last_line_width(&lhs_result) + pp.infix.len()) - .and_then(|s| s.sub_width(pp.suffix.len())) - .and_then(|rhs_shape| rhs.rewrite(context, rhs_shape)); - if let Some(ref rhs_result) = rhs_orig_result { - // If the rhs looks like block expression, we allow it to stay on the same line - // with the lhs even if it is multi-lined. - let allow_same_line = rhs_result - .lines() - .next() - .map(|first_line| first_line.ends_with('{')) - .unwrap_or(false); - if !rhs_result.contains('\n') || allow_same_line { - let one_line_width = last_line_width(&lhs_result) + pp.infix.len() - + first_line_width(rhs_result) + pp.suffix.len(); - if one_line_width <= shape.width { - return Some(format!( - "{}{}{}{}", - lhs_result, pp.infix, rhs_result, pp.suffix - )); - } - } - } - - // We have to use multiple lines. - // Re-evaluate the rhs because we have more space now: - let mut rhs_shape = match context.config.indent_style() { - IndentStyle::Visual => shape - .sub_width(pp.suffix.len() + pp.prefix.len())? - .visual_indent(pp.prefix.len()), - IndentStyle::Block => { - // Try to calculate the initial constraint on the right hand side. - let rhs_overhead = shape.rhs_overhead(context.config); - Shape::indented(shape.indent.block_indent(context.config), context.config) - .sub_width(rhs_overhead)? - } - }; - let infix = match separator_place { - SeparatorPlace::Back => pp.infix.trim_right(), - SeparatorPlace::Front => pp.infix.trim_left(), - }; - if separator_place == SeparatorPlace::Front { - rhs_shape = rhs_shape.offset_left(infix.len())?; - } - let rhs_result = rhs.rewrite(context, rhs_shape)?; - let indent_str = rhs_shape.indent.to_string(context.config); - let infix_with_sep = match separator_place { - SeparatorPlace::Back => format!("{}\n{}", infix, indent_str), - SeparatorPlace::Front => format!("\n{}{}", indent_str, infix), - }; - Some(format!( - "{}{}{}{}", - lhs_result, infix_with_sep, rhs_result, pp.suffix - )) -} - -pub fn rewrite_array<T: Rewrite + Spanned + ToExpr>( - exprs: &[&T], - span: Span, - context: &RewriteContext, - shape: Shape, - trailing_comma: bool, -) -> Option<String> { - let bracket_size = if context.config.spaces_within_parens_and_brackets() { - 2 // "[ " - } else { - 1 // "[" - }; - - let nested_shape = match context.config.indent_style() { - IndentStyle::Block => shape - .block() - .block_indent(context.config.tab_spaces()) - .with_max_width(context.config) - .sub_width(1)?, - IndentStyle::Visual => shape - .visual_indent(bracket_size) - .sub_width(bracket_size * 2)?, - }; - - let items = itemize_list( - context.codemap, - exprs.iter(), - "]", - ",", - |item| item.span().lo(), - |item| item.span().hi(), - |item| item.rewrite(context, nested_shape), - span.lo(), - span.hi(), - false, - ).collect::<Vec<_>>(); - - if items.is_empty() { - if context.config.spaces_within_parens_and_brackets() { - return Some("[ ]".to_string()); - } else { - return Some("[]".to_string()); - } - } - - let tactic = array_tactic(context, shape, nested_shape, exprs, &items, bracket_size); - let ends_with_newline = tactic.ends_with_newline(context.config.indent_style()); - - let fmt = ListFormatting { - tactic, - separator: ",", - trailing_separator: if trailing_comma { - SeparatorTactic::Always - } else if context.inside_macro && !exprs.is_empty() { - let ends_with_bracket = context.snippet(span).ends_with(']'); - let bracket_offset = if ends_with_bracket { 1 } else { 0 }; - let snippet = context.snippet(mk_sp(span.lo(), span.hi() - BytePos(bracket_offset))); - let last_char_index = snippet.rfind(|c: char| !c.is_whitespace())?; - if &snippet[last_char_index..last_char_index + 1] == "," { - SeparatorTactic::Always - } else { - SeparatorTactic::Never - } - } else if context.config.indent_style() == IndentStyle::Visual { - SeparatorTactic::Never - } else { - SeparatorTactic::Vertical - }, - separator_place: SeparatorPlace::Back, - shape: nested_shape, - ends_with_newline, - preserve_newline: false, - config: context.config, - }; - let list_str = write_list(&items, &fmt)?; - - let result = if context.config.indent_style() == IndentStyle::Visual - || tactic == DefinitiveListTactic::Horizontal - { - if context.config.spaces_within_parens_and_brackets() && !list_str.is_empty() { - format!("[ {} ]", list_str) - } else { - format!("[{}]", list_str) - } - } else { - format!( - "[\n{}{}\n{}]", - nested_shape.indent.to_string(context.config), - list_str, - shape.block().indent.to_string(context.config) - ) - }; - - Some(result) -} - -fn array_tactic<T: Rewrite + Spanned + ToExpr>( - context: &RewriteContext, - shape: Shape, - nested_shape: Shape, - exprs: &[&T], - items: &[ListItem], - bracket_size: usize, -) -> DefinitiveListTactic { - let has_long_item = items - .iter() - .any(|li| li.item.as_ref().map(|s| s.len() > 10).unwrap_or(false)); - - match context.config.indent_style() { - IndentStyle::Block => { - let tactic = match shape.width.checked_sub(2 * bracket_size) { - Some(width) => { - let tactic = ListTactic::LimitedHorizontalVertical( - context.config.width_heuristics().array_width, - ); - definitive_tactic(items, tactic, Separator::Comma, width) - } - None => DefinitiveListTactic::Vertical, - }; - if tactic == DefinitiveListTactic::Vertical && !has_long_item - && is_every_args_simple(exprs) - { - DefinitiveListTactic::Mixed - } else { - tactic - } - } - IndentStyle::Visual => { - if has_long_item || items.iter().any(ListItem::is_multiline) { - definitive_tactic( - items, - ListTactic::LimitedHorizontalVertical( - context.config.width_heuristics().array_width, - ), - Separator::Comma, - nested_shape.width, - ) - } else { - DefinitiveListTactic::Mixed - } - } - } -} - -fn nop_block_collapse(block_str: Option<String>, budget: usize) -> Option<String> { - debug!("nop_block_collapse {:?} {}", block_str, budget); - block_str.map(|block_str| { - if block_str.starts_with('{') && budget >= 2 - && (block_str[1..].find(|c: char| !c.is_whitespace()).unwrap() == block_str.len() - 2) - { - "{}".to_owned() - } else { - block_str.to_owned() - } - }) -} - -fn rewrite_empty_block( - context: &RewriteContext, - block: &ast::Block, - shape: Shape, -) -> Option<String> { - if block.stmts.is_empty() && !block_contains_comment(block, context.codemap) && shape.width >= 2 - { - return Some("{}".to_owned()); - } - - // If a block contains only a single-line comment, then leave it on one line. - let user_str = context.snippet(block.span); - let user_str = user_str.trim(); - if user_str.starts_with('{') && user_str.ends_with('}') { - let comment_str = user_str[1..user_str.len() - 1].trim(); - if block.stmts.is_empty() && !comment_str.contains('\n') && !comment_str.starts_with("//") - && comment_str.len() + 4 <= shape.width - { - return Some(format!("{{ {} }}", comment_str)); - } - } - - None -} - -fn block_prefix(context: &RewriteContext, block: &ast::Block, shape: Shape) -> Option<String> { - Some(match block.rules { - ast::BlockCheckMode::Unsafe(..) => { - let snippet = context.snippet(block.span); - let open_pos = snippet.find_uncommented("{")?; - // Extract comment between unsafe and block start. - let trimmed = &snippet[6..open_pos].trim(); - - if !trimmed.is_empty() { - // 9 = "unsafe {".len(), 7 = "unsafe ".len() - let budget = shape.width.checked_sub(9)?; - format!( - "unsafe {} ", - rewrite_comment( - trimmed, - true, - Shape::legacy(budget, shape.indent + 7), - context.config, - )? - ) - } else { - "unsafe ".to_owned() - } - } - ast::BlockCheckMode::Default => String::new(), - }) -} - -fn rewrite_single_line_block( - context: &RewriteContext, - prefix: &str, - block: &ast::Block, - shape: Shape, -) -> Option<String> { - if is_simple_block(block, context.codemap) { - let expr_shape = shape.offset_left(last_line_width(prefix))?; - let expr_str = block.stmts[0].rewrite(context, expr_shape)?; - let result = format!("{}{{ {} }}", prefix, expr_str); - if result.len() <= shape.width && !result.contains('\n') { - return Some(result); - } - } - None -} - -pub fn rewrite_block_with_visitor( - context: &RewriteContext, - prefix: &str, - block: &ast::Block, - shape: Shape, - has_braces: bool, -) -> Option<String> { - if let rw @ Some(_) = rewrite_empty_block(context, block, shape) { - return rw; - } - - let mut visitor = FmtVisitor::from_context(context); - visitor.block_indent = shape.indent; - visitor.is_if_else_block = context.is_if_else_block; - match block.rules { - ast::BlockCheckMode::Unsafe(..) => { - let snippet = context.snippet(block.span); - let open_pos = snippet.find_uncommented("{")?; - visitor.last_pos = block.span.lo() + BytePos(open_pos as u32) - } - ast::BlockCheckMode::Default => visitor.last_pos = block.span.lo(), - } - - visitor.visit_block(block, None, has_braces); - Some(format!("{}{}", prefix, visitor.buffer)) -} - -impl Rewrite for ast::Block { - fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> { - // shape.width is used only for the single line case: either the empty block `{}`, - // or an unsafe expression `unsafe { e }`. - if let rw @ Some(_) = rewrite_empty_block(context, self, shape) { - return rw; - } - - let prefix = block_prefix(context, self, shape)?; - - let result = rewrite_block_with_visitor(context, &prefix, self, shape, true); - if let Some(ref result_str) = result { - if result_str.lines().count() <= 3 { - if let rw @ Some(_) = rewrite_single_line_block(context, &prefix, self, shape) { - return rw; - } - } - } - - result - } -} - -impl Rewrite for ast::Stmt { - fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> { - skip_out_of_file_lines_range!(context, self.span()); - - let result = match self.node { - ast::StmtKind::Local(ref local) => local.rewrite(context, shape), - ast::StmtKind::Expr(ref ex) | ast::StmtKind::Semi(ref ex) => { - let suffix = if semicolon_for_stmt(context, self) { - ";" - } else { - "" - }; - - let shape = shape.sub_width(suffix.len())?; - format_expr(ex, ExprType::Statement, context, shape).map(|s| s + suffix) - } - ast::StmtKind::Mac(..) | ast::StmtKind::Item(..) => None, - }; - result.and_then(|res| recover_comment_removed(res, self.span(), context)) - } -} - -// Rewrite condition if the given expression has one. -pub fn rewrite_cond(context: &RewriteContext, expr: &ast::Expr, shape: Shape) -> Option<String> { - match expr.node { - ast::ExprKind::Match(ref cond, _) => { - // `match `cond` {` - let cond_shape = match context.config.indent_style() { - IndentStyle::Visual => shape.shrink_left(6).and_then(|s| s.sub_width(2))?, - IndentStyle::Block => shape.offset_left(8)?, - }; - cond.rewrite(context, cond_shape) - } - _ => to_control_flow(expr, ExprType::SubExpression).and_then(|control_flow| { - let alt_block_sep = - String::from("\n") + &shape.indent.block_only().to_string(context.config); - control_flow - .rewrite_cond(context, shape, &alt_block_sep) - .and_then(|rw| Some(rw.0)) - }), - } -} - -// Abstraction over control flow expressions -#[derive(Debug)] -struct ControlFlow<'a> { - cond: Option<&'a ast::Expr>, - block: &'a ast::Block, - else_block: Option<&'a ast::Expr>, - label: Option<ast::Label>, - pat: Option<&'a ast::Pat>, - keyword: &'a str, - matcher: &'a str, - connector: &'a str, - allow_single_line: bool, - // True if this is an `if` expression in an `else if` :-( hacky - nested_if: bool, - span: Span, -} - -fn to_control_flow(expr: &ast::Expr, expr_type: ExprType) -> Option<ControlFlow> { - match expr.node { - ast::ExprKind::If(ref cond, ref if_block, ref else_block) => Some(ControlFlow::new_if( - cond, - None, - if_block, - else_block.as_ref().map(|e| &**e), - expr_type == ExprType::SubExpression, - false, - expr.span, - )), - ast::ExprKind::IfLet(ref pat, ref cond, ref if_block, ref else_block) => { - Some(ControlFlow::new_if( - cond, - Some(pat), - if_block, - else_block.as_ref().map(|e| &**e), - expr_type == ExprType::SubExpression, - false, - expr.span, - )) - } - ast::ExprKind::ForLoop(ref pat, ref cond, ref block, label) => { - Some(ControlFlow::new_for(pat, cond, block, label, expr.span)) - } - ast::ExprKind::Loop(ref block, label) => { - Some(ControlFlow::new_loop(block, label, expr.span)) - } - ast::ExprKind::While(ref cond, ref block, label) => { - Some(ControlFlow::new_while(None, cond, block, label, expr.span)) - } - ast::ExprKind::WhileLet(ref pat, ref cond, ref block, label) => Some( - ControlFlow::new_while(Some(pat), cond, block, label, expr.span), - ), - _ => None, - } -} - -impl<'a> ControlFlow<'a> { - fn new_if( - cond: &'a ast::Expr, - pat: Option<&'a ast::Pat>, - block: &'a ast::Block, - else_block: Option<&'a ast::Expr>, - allow_single_line: bool, - nested_if: bool, - span: Span, - ) -> ControlFlow<'a> { - ControlFlow { - cond: Some(cond), - block, - else_block, - label: None, - pat, - keyword: "if", - matcher: match pat { - Some(..) => "let", - None => "", - }, - connector: " =", - allow_single_line, - nested_if, - span, - } - } - - fn new_loop(block: &'a ast::Block, label: Option<ast::Label>, span: Span) -> ControlFlow<'a> { - ControlFlow { - cond: None, - block, - else_block: None, - label, - pat: None, - keyword: "loop", - matcher: "", - connector: "", - allow_single_line: false, - nested_if: false, - span, - } - } - - fn new_while( - pat: Option<&'a ast::Pat>, - cond: &'a ast::Expr, - block: &'a ast::Block, - label: Option<ast::Label>, - span: Span, - ) -> ControlFlow<'a> { - ControlFlow { - cond: Some(cond), - block, - else_block: None, - label, - pat, - keyword: "while", - matcher: match pat { - Some(..) => "let", - None => "", - }, - connector: " =", - allow_single_line: false, - nested_if: false, - span, - } - } - - fn new_for( - pat: &'a ast::Pat, - cond: &'a ast::Expr, - block: &'a ast::Block, - label: Option<ast::Label>, - span: Span, - ) -> ControlFlow<'a> { - ControlFlow { - cond: Some(cond), - block, - else_block: None, - label, - pat: Some(pat), - keyword: "for", - matcher: "", - connector: " in", - allow_single_line: false, - nested_if: false, - span, - } - } - - fn rewrite_single_line( - &self, - pat_expr_str: &str, - context: &RewriteContext, - width: usize, - ) -> Option<String> { - assert!(self.allow_single_line); - let else_block = self.else_block?; - let fixed_cost = self.keyword.len() + " { } else { }".len(); - - if let ast::ExprKind::Block(ref else_node) = else_block.node { - if !is_simple_block(self.block, context.codemap) - || !is_simple_block(else_node, context.codemap) - || pat_expr_str.contains('\n') - { - return None; - } - - let new_width = width.checked_sub(pat_expr_str.len() + fixed_cost)?; - let expr = &self.block.stmts[0]; - let if_str = expr.rewrite(context, Shape::legacy(new_width, Indent::empty()))?; - - let new_width = new_width.checked_sub(if_str.len())?; - let else_expr = &else_node.stmts[0]; - let else_str = else_expr.rewrite(context, Shape::legacy(new_width, Indent::empty()))?; - - if if_str.contains('\n') || else_str.contains('\n') { - return None; - } - - let result = format!( - "{} {} {{ {} }} else {{ {} }}", - self.keyword, pat_expr_str, if_str, else_str - ); - - if result.len() <= width { - return Some(result); - } - } - - None - } -} - -impl<'a> ControlFlow<'a> { - fn rewrite_cond( - &self, - context: &RewriteContext, - shape: Shape, - alt_block_sep: &str, - ) -> Option<(String, usize)> { - // Do not take the rhs overhead from the upper expressions into account - // when rewriting pattern. - let new_width = context - .config - .max_width() - .checked_sub(shape.used_width()) - .unwrap_or(0); - let fresh_shape = Shape { - width: new_width, - ..shape - }; - let constr_shape = if self.nested_if { - // We are part of an if-elseif-else chain. Our constraints are tightened. - // 7 = "} else " .len() - fresh_shape.offset_left(7)? - } else { - fresh_shape - }; - - let label_string = rewrite_label(self.label); - // 1 = space after keyword. - let offset = self.keyword.len() + label_string.len() + 1; - - let pat_expr_string = match self.cond { - Some(cond) => rewrite_pat_expr( - context, - self.pat, - cond, - self.matcher, - self.connector, - self.keyword, - constr_shape, - offset, - )?, - None => String::new(), - }; - - let brace_overhead = - if context.config.control_brace_style() != ControlBraceStyle::AlwaysNextLine { - // 2 = ` {` - 2 - } else { - 0 - }; - let one_line_budget = context - .config - .max_width() - .checked_sub(constr_shape.used_width() + offset + brace_overhead) - .unwrap_or(0); - let force_newline_brace = (pat_expr_string.contains('\n') - || pat_expr_string.len() > one_line_budget) - && !last_line_extendable(&pat_expr_string); - - // Try to format if-else on single line. - if self.allow_single_line - && context - .config - .width_heuristics() - .single_line_if_else_max_width > 0 - { - let trial = self.rewrite_single_line(&pat_expr_string, context, shape.width); - - if let Some(cond_str) = trial { - if cond_str.len() - <= context - .config - .width_heuristics() - .single_line_if_else_max_width - { - return Some((cond_str, 0)); - } - } - } - - let cond_span = if let Some(cond) = self.cond { - cond.span - } else { - mk_sp(self.block.span.lo(), self.block.span.lo()) - }; - - // `for event in event` - // Do not include label in the span. - let lo = self.label.map_or(self.span.lo(), |label| label.span.hi()); - let between_kwd_cond = mk_sp( - context - .codemap - .span_after(mk_sp(lo, self.span.hi()), self.keyword.trim()), - self.pat.map_or(cond_span.lo(), |p| { - if self.matcher.is_empty() { - p.span.lo() - } else { - context.codemap.span_before(self.span, self.matcher.trim()) - } - }), - ); - - let between_kwd_cond_comment = extract_comment(between_kwd_cond, context, shape); - - let after_cond_comment = - extract_comment(mk_sp(cond_span.hi(), self.block.span.lo()), context, shape); - - let block_sep = if self.cond.is_none() && between_kwd_cond_comment.is_some() { - "" - } else if context.config.control_brace_style() == ControlBraceStyle::AlwaysNextLine - || force_newline_brace - { - alt_block_sep - } else { - " " - }; - - let used_width = if pat_expr_string.contains('\n') { - last_line_width(&pat_expr_string) - } else { - // 2 = spaces after keyword and condition. - label_string.len() + self.keyword.len() + pat_expr_string.len() + 2 - }; - - Some(( - format!( - "{}{}{}{}{}", - label_string, - self.keyword, - between_kwd_cond_comment.as_ref().map_or( - if pat_expr_string.is_empty() || pat_expr_string.starts_with('\n') { - "" - } else { - " " - }, - |s| &**s, - ), - pat_expr_string, - after_cond_comment.as_ref().map_or(block_sep, |s| &**s) - ), - used_width, - )) - } -} - -impl<'a> Rewrite for ControlFlow<'a> { - fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> { - debug!("ControlFlow::rewrite {:?} {:?}", self, shape); - - let alt_block_sep = String::from("\n") + &shape.indent.to_string(context.config); - let (cond_str, used_width) = self.rewrite_cond(context, shape, &alt_block_sep)?; - // If `used_width` is 0, it indicates that whole control flow is written in a single line. - if used_width == 0 { - return Some(cond_str); - } - - let block_width = shape.width.checked_sub(used_width).unwrap_or(0); - // This is used only for the empty block case: `{}`. So, we use 1 if we know - // we should avoid the single line case. - let block_width = if self.else_block.is_some() || self.nested_if { - min(1, block_width) - } else { - block_width - }; - let block_shape = Shape { - width: block_width, - ..shape - }; - let mut block_context = context.clone(); - block_context.is_if_else_block = self.else_block.is_some(); - let block_str = - rewrite_block_with_visitor(&block_context, "", self.block, block_shape, true)?; - - let mut result = format!("{}{}", cond_str, block_str); - - if let Some(else_block) = self.else_block { - let shape = Shape::indented(shape.indent, context.config); - let mut last_in_chain = false; - let rewrite = match else_block.node { - // If the else expression is another if-else expression, prevent it - // from being formatted on a single line. - // Note how we're passing the original shape, as the - // cost of "else" should not cascade. - ast::ExprKind::IfLet(ref pat, ref cond, ref if_block, ref next_else_block) => { - ControlFlow::new_if( - cond, - Some(pat), - if_block, - next_else_block.as_ref().map(|e| &**e), - false, - true, - mk_sp(else_block.span.lo(), self.span.hi()), - ).rewrite(context, shape) - } - ast::ExprKind::If(ref cond, ref if_block, ref next_else_block) => { - ControlFlow::new_if( - cond, - None, - if_block, - next_else_block.as_ref().map(|e| &**e), - false, - true, - mk_sp(else_block.span.lo(), self.span.hi()), - ).rewrite(context, shape) - } - _ => { - last_in_chain = true; - // When rewriting a block, the width is only used for single line - // blocks, passing 1 lets us avoid that. - let else_shape = Shape { - width: min(1, shape.width), - ..shape - }; - format_expr(else_block, ExprType::Statement, context, else_shape) - } - }; - - let between_kwd_else_block = mk_sp( - self.block.span.hi(), - context - .codemap - .span_before(mk_sp(self.block.span.hi(), else_block.span.lo()), "else"), - ); - let between_kwd_else_block_comment = - extract_comment(between_kwd_else_block, context, shape); - - let after_else = mk_sp( - context - .codemap - .span_after(mk_sp(self.block.span.hi(), else_block.span.lo()), "else"), - else_block.span.lo(), - ); - let after_else_comment = extract_comment(after_else, context, shape); - - let between_sep = match context.config.control_brace_style() { - ControlBraceStyle::AlwaysNextLine | ControlBraceStyle::ClosingNextLine => { - &*alt_block_sep - } - ControlBraceStyle::AlwaysSameLine => " ", - }; - let after_sep = match context.config.control_brace_style() { - ControlBraceStyle::AlwaysNextLine if last_in_chain => &*alt_block_sep, - _ => " ", - }; - - result.push_str(&format!( - "{}else{}", - between_kwd_else_block_comment - .as_ref() - .map_or(between_sep, |s| &**s), - after_else_comment.as_ref().map_or(after_sep, |s| &**s), - )); - result.push_str(&rewrite?); - } - - Some(result) - } -} - -fn rewrite_label(opt_label: Option<ast::Label>) -> Cow<'static, str> { - match opt_label { - Some(label) => Cow::from(format!("{}: ", label.ident)), - None => Cow::from(""), - } -} - -fn extract_comment(span: Span, context: &RewriteContext, shape: Shape) -> Option<String> { - match rewrite_missing_comment(span, shape, context) { - Some(ref comment) if !comment.is_empty() => Some(format!( - "\n{indent}{}\n{indent}", - comment, - indent = shape.indent.to_string(context.config) - )), - _ => None, - } -} - -pub fn block_contains_comment(block: &ast::Block, codemap: &CodeMap) -> bool { - let snippet = codemap.span_to_snippet(block.span).unwrap(); - contains_comment(&snippet) -} - -// Checks that a block contains no statements, an expression and no comments. -// FIXME: incorrectly returns false when comment is contained completely within -// the expression. -pub fn is_simple_block(block: &ast::Block, codemap: &CodeMap) -> bool { - (block.stmts.len() == 1 && stmt_is_expr(&block.stmts[0]) - && !block_contains_comment(block, codemap)) -} - -/// Checks whether a block contains at most one statement or expression, and no comments. -pub fn is_simple_block_stmt(block: &ast::Block, codemap: &CodeMap) -> bool { - block.stmts.len() <= 1 && !block_contains_comment(block, codemap) -} - -/// Checks whether a block contains no statements, expressions, or comments. -pub fn is_empty_block(block: &ast::Block, codemap: &CodeMap) -> bool { - block.stmts.is_empty() && !block_contains_comment(block, codemap) -} - -pub fn stmt_is_expr(stmt: &ast::Stmt) -> bool { - match stmt.node { - ast::StmtKind::Expr(..) => true, - _ => false, - } -} - -pub fn is_unsafe_block(block: &ast::Block) -> bool { - if let ast::BlockCheckMode::Unsafe(..) = block.rules { - true - } else { - false - } -} - -// A simple wrapper type against ast::Arm. Used inside write_list(). -struct ArmWrapper<'a> { - pub arm: &'a ast::Arm, - // True if the arm is the last one in match expression. Used to decide on whether we should add - // trailing comma to the match arm when `config.trailing_comma() == Never`. - pub is_last: bool, -} - -impl<'a> ArmWrapper<'a> { - pub fn new(arm: &'a ast::Arm, is_last: bool) -> ArmWrapper<'a> { - ArmWrapper { arm, is_last } - } -} - -impl<'a> Rewrite for ArmWrapper<'a> { - fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> { - rewrite_match_arm(context, self.arm, shape, self.is_last) - } -} - -fn rewrite_match( - context: &RewriteContext, - cond: &ast::Expr, - arms: &[ast::Arm], - shape: Shape, - span: Span, - attrs: &[ast::Attribute], -) -> Option<String> { - // Do not take the rhs overhead from the upper expressions into account - // when rewriting match condition. - let cond_shape = Shape { - width: context.budget(shape.used_width()), - ..shape - }; - // 6 = `match ` - let cond_shape = match context.config.indent_style() { - IndentStyle::Visual => cond_shape.shrink_left(6)?, - IndentStyle::Block => cond_shape.offset_left(6)?, - }; - let cond_str = cond.rewrite(context, cond_shape)?; - let alt_block_sep = String::from("\n") + &shape.indent.to_string(context.config); - let block_sep = match context.config.control_brace_style() { - ControlBraceStyle::AlwaysNextLine => &alt_block_sep, - _ if last_line_extendable(&cond_str) => " ", - // 2 = ` {` - _ if cond_str.contains('\n') || cond_str.len() + 2 > cond_shape.width => &alt_block_sep, - _ => " ", - }; - - let nested_indent_str = shape - .indent - .block_indent(context.config) - .to_string(context.config); - // Inner attributes. - let inner_attrs = &inner_attributes(attrs); - let inner_attrs_str = if inner_attrs.is_empty() { - String::new() - } else { - inner_attrs - .rewrite(context, shape) - .map(|s| format!("{}{}\n", nested_indent_str, s))? - }; - - let open_brace_pos = if inner_attrs.is_empty() { - let hi = if arms.is_empty() { - span.hi() - } else { - arms[0].span().lo() - }; - context.codemap.span_after(mk_sp(cond.span.hi(), hi), "{") - } else { - inner_attrs[inner_attrs.len() - 1].span().hi() - }; - - if arms.is_empty() { - let snippet = context.snippet(mk_sp(open_brace_pos, span.hi() - BytePos(1))); - if snippet.trim().is_empty() { - Some(format!("match {} {{}}", cond_str)) - } else { - // Empty match with comments or inner attributes? We are not going to bother, sorry ;) - Some(context.snippet(span).to_owned()) - } - } else { - Some(format!( - "match {}{}{{\n{}{}{}\n{}}}", - cond_str, - block_sep, - inner_attrs_str, - nested_indent_str, - rewrite_match_arms(context, arms, shape, span, open_brace_pos)?, - shape.indent.to_string(context.config), - )) - } -} - -fn arm_comma(config: &Config, body: &ast::Expr, is_last: bool) -> &'static str { - if is_last && config.trailing_comma() == SeparatorTactic::Never { - "" - } else if config.match_block_trailing_comma() { - "," - } else if let ast::ExprKind::Block(ref block) = body.node { - if let ast::BlockCheckMode::Default = block.rules { - "" - } else { - "," - } - } else { - "," - } -} - -fn rewrite_match_arms( - context: &RewriteContext, - arms: &[ast::Arm], - shape: Shape, - span: Span, - open_brace_pos: BytePos, -) -> Option<String> { - let arm_shape = shape - .block_indent(context.config.tab_spaces()) - .with_max_width(context.config); - - let arm_len = arms.len(); - let is_last_iter = repeat(false) - .take(arm_len.checked_sub(1).unwrap_or(0)) - .chain(repeat(true)); - let items = itemize_list( - context.codemap, - arms.iter() - .zip(is_last_iter) - .map(|(arm, is_last)| ArmWrapper::new(arm, is_last)), - "}", - "|", - |arm| arm.arm.span().lo(), - |arm| arm.arm.span().hi(), - |arm| arm.rewrite(context, arm_shape), - open_brace_pos, - span.hi(), - false, - ); - let arms_vec: Vec<_> = items.collect(); - let fmt = ListFormatting { - tactic: DefinitiveListTactic::Vertical, - // We will add/remove commas inside `arm.rewrite()`, and hence no separator here. - separator: "", - trailing_separator: SeparatorTactic::Never, - separator_place: SeparatorPlace::Back, - shape: arm_shape, - ends_with_newline: true, - preserve_newline: true, - config: context.config, - }; - - write_list(&arms_vec, &fmt) -} - -fn rewrite_match_arm( - context: &RewriteContext, - arm: &ast::Arm, - shape: Shape, - is_last: bool, -) -> Option<String> { - let (missing_span, attrs_str) = if !arm.attrs.is_empty() { - if contains_skip(&arm.attrs) { - let (_, body) = flatten_arm_body(context, &arm.body); - // `arm.span()` does not include trailing comma, add it manually. - return Some(format!( - "{}{}", - context.snippet(arm.span()), - arm_comma(context.config, body, is_last), - )); - } - let missing_span = mk_sp( - arm.attrs[arm.attrs.len() - 1].span.hi(), - arm.pats[0].span.lo(), - ); - (missing_span, arm.attrs.rewrite(context, shape)?) - } else { - (mk_sp(arm.span().lo(), arm.span().lo()), String::new()) - }; - let pats_str = - rewrite_match_pattern(context, &arm.pats, &arm.guard, shape).and_then(|pats_str| { - combine_strs_with_missing_comments( - context, - &attrs_str, - &pats_str, - missing_span, - shape, - false, - ) - })?; - rewrite_match_body( - context, - &arm.body, - &pats_str, - shape, - arm.guard.is_some(), - is_last, - ) -} - -/// Returns true if the given pattern is short. A short pattern is defined by the following grammer: -/// -/// [small, ntp]: -/// - single token -/// - `&[single-line, ntp]` -/// -/// [small]: -/// - `[small, ntp]` -/// - unary tuple constructor `([small, ntp])` -/// - `&[small]` -fn is_short_pattern(pat: &ast::Pat, pat_str: &str) -> bool { - // We also require that the pattern is reasonably 'small' with its literal width. - pat_str.len() <= 20 && !pat_str.contains('\n') && is_short_pattern_inner(pat) -} - -fn is_short_pattern_inner(pat: &ast::Pat) -> bool { - match pat.node { - ast::PatKind::Wild | ast::PatKind::Lit(_) => true, - ast::PatKind::Ident(_, _, ref pat) => pat.is_none(), - ast::PatKind::Struct(..) - | ast::PatKind::Mac(..) - | ast::PatKind::Slice(..) - | ast::PatKind::Path(..) - | ast::PatKind::Range(..) => false, - ast::PatKind::Tuple(ref subpats, _) => subpats.len() <= 1, - ast::PatKind::TupleStruct(ref path, ref subpats, _) => { - path.segments.len() <= 1 && subpats.len() <= 1 - } - ast::PatKind::Box(ref p) | ast::PatKind::Ref(ref p, _) => is_short_pattern_inner(&*p), - } -} - -fn rewrite_match_pattern( - context: &RewriteContext, - pats: &[ptr::P<ast::Pat>], - guard: &Option<ptr::P<ast::Expr>>, - shape: Shape, -) -> Option<String> { - // Patterns - // 5 = ` => {` - let pat_shape = shape.sub_width(5)?; - - let pat_strs = pats.iter() - .map(|p| p.rewrite(context, pat_shape)) - .collect::<Option<Vec<_>>>()?; - - let use_mixed_layout = pats.iter() - .zip(pat_strs.iter()) - .all(|(pat, pat_str)| is_short_pattern(pat, pat_str)); - let items: Vec<_> = pat_strs.into_iter().map(ListItem::from_str).collect(); - let tactic = if use_mixed_layout { - DefinitiveListTactic::Mixed - } else { - definitive_tactic( - &items, - ListTactic::HorizontalVertical, - Separator::VerticalBar, - pat_shape.width, - ) - }; - let fmt = ListFormatting { - tactic, - separator: " |", - trailing_separator: SeparatorTactic::Never, - separator_place: context.config.binop_separator(), - shape: pat_shape, - ends_with_newline: false, - preserve_newline: false, - config: context.config, - }; - let pats_str = write_list(&items, &fmt)?; - - // Guard - let guard_str = rewrite_guard(context, guard, shape, trimmed_last_line_width(&pats_str))?; - - Some(format!("{}{}", pats_str, guard_str)) -} - -// (extend, body) -// @extend: true if the arm body can be put next to `=>` -// @body: flattened body, if the body is block with a single expression -fn flatten_arm_body<'a>(context: &'a RewriteContext, body: &'a ast::Expr) -> (bool, &'a ast::Expr) { - match body.node { - ast::ExprKind::Block(ref block) - if !is_unsafe_block(block) && is_simple_block(block, context.codemap) => - { - if let ast::StmtKind::Expr(ref expr) = block.stmts[0].node { - ( - !context.config.force_multiline_blocks() && can_extend_match_arm_body(expr), - &*expr, - ) - } else { - (false, &*body) - } - } - _ => ( - !context.config.force_multiline_blocks() && body.can_be_overflowed(context, 1), - &*body, - ), - } -} - -fn rewrite_match_body( - context: &RewriteContext, - body: &ptr::P<ast::Expr>, - pats_str: &str, - shape: Shape, - has_guard: bool, - is_last: bool, -) -> Option<String> { - let (extend, body) = flatten_arm_body(context, body); - let (is_block, is_empty_block) = if let ast::ExprKind::Block(ref block) = body.node { - (true, is_empty_block(block, context.codemap)) - } else { - (false, false) - }; - - let comma = arm_comma(context.config, body, is_last); - let alt_block_sep = String::from("\n") + &shape.indent.to_string(context.config); - let alt_block_sep = alt_block_sep.as_str(); - - let combine_orig_body = |body_str: &str| { - let block_sep = match context.config.control_brace_style() { - ControlBraceStyle::AlwaysNextLine if is_block => alt_block_sep, - _ => " ", - }; - - Some(format!("{} =>{}{}{}", pats_str, block_sep, body_str, comma)) - }; - - let forbid_same_line = has_guard && pats_str.contains('\n') && !is_empty_block; - let next_line_indent = if !is_block || is_empty_block { - shape.indent.block_indent(context.config) - } else { - shape.indent - }; - let combine_next_line_body = |body_str: &str| { - if is_block { - return Some(format!( - "{} =>\n{}{}", - pats_str, - next_line_indent.to_string(context.config), - body_str - )); - } - - let indent_str = shape.indent.to_string(context.config); - let nested_indent_str = next_line_indent.to_string(context.config); - let (body_prefix, body_suffix) = if context.config.match_arm_blocks() { - let comma = if context.config.match_block_trailing_comma() { - "," - } else { - "" - }; - ("{", format!("\n{}}}{}", indent_str, comma)) - } else { - ("", String::from(",")) - }; - - let block_sep = match context.config.control_brace_style() { - ControlBraceStyle::AlwaysNextLine => format!("{}{}\n", alt_block_sep, body_prefix), - _ if body_prefix.is_empty() => "\n".to_owned(), - _ if forbid_same_line => format!("{}{}\n", alt_block_sep, body_prefix), - _ => format!(" {}\n", body_prefix), - } + &nested_indent_str; - - Some(format!( - "{} =>{}{}{}", - pats_str, block_sep, body_str, body_suffix - )) - }; - - // Let's try and get the arm body on the same line as the condition. - // 4 = ` => `.len() - let orig_body_shape = shape - .offset_left(extra_offset(pats_str, shape) + 4) - .and_then(|shape| shape.sub_width(comma.len())); - let orig_body = if let Some(body_shape) = orig_body_shape { - let rewrite = nop_block_collapse( - format_expr(body, ExprType::Statement, context, body_shape), - body_shape.width, - ); - - match rewrite { - Some(ref body_str) - if !forbid_same_line - && (is_block - || (!body_str.contains('\n') && body_str.len() <= body_shape.width)) => - { - return combine_orig_body(body_str); - } - _ => rewrite, - } - } else { - None - }; - let orig_budget = orig_body_shape.map_or(0, |shape| shape.width); - - // Try putting body on the next line and see if it looks better. - let next_line_body_shape = Shape::indented(next_line_indent, context.config); - let next_line_body = nop_block_collapse( - format_expr(body, ExprType::Statement, context, next_line_body_shape), - next_line_body_shape.width, - ); - match (orig_body, next_line_body) { - (Some(ref orig_str), Some(ref next_line_str)) - if forbid_same_line || prefer_next_line(orig_str, next_line_str) => - { - combine_next_line_body(next_line_str) - } - (Some(ref orig_str), _) if extend && first_line_width(orig_str) <= orig_budget => { - combine_orig_body(orig_str) - } - (Some(ref orig_str), Some(ref next_line_str)) if orig_str.contains('\n') => { - combine_next_line_body(next_line_str) - } - (None, Some(ref next_line_str)) => combine_next_line_body(next_line_str), - (None, None) => None, - (Some(ref orig_str), _) => combine_orig_body(orig_str), - } -} - -// The `if ...` guard on a match arm. -fn rewrite_guard( - context: &RewriteContext, - guard: &Option<ptr::P<ast::Expr>>, - shape: Shape, - // The amount of space used up on this line for the pattern in - // the arm (excludes offset). - pattern_width: usize, -) -> Option<String> { - if let Some(ref guard) = *guard { - // First try to fit the guard string on the same line as the pattern. - // 4 = ` if `, 5 = ` => {` - let cond_shape = shape - .offset_left(pattern_width + 4) - .and_then(|s| s.sub_width(5)); - if let Some(cond_shape) = cond_shape { - if let Some(cond_str) = guard.rewrite(context, cond_shape) { - if !cond_str.contains('\n') || pattern_width <= context.config.tab_spaces() { - return Some(format!(" if {}", cond_str)); - } - } - } - - // Not enough space to put the guard after the pattern, try a newline. - // 3 = `if `, 5 = ` => {` - let cond_shape = Shape::indented(shape.indent.block_indent(context.config), context.config) - .offset_left(3) - .and_then(|s| s.sub_width(5)); - if let Some(cond_shape) = cond_shape { - if let Some(cond_str) = guard.rewrite(context, cond_shape) { - return Some(format!( - "\n{}if {}", - cond_shape.indent.to_string(context.config), - cond_str - )); - } - } - - None - } else { - Some(String::new()) - } -} - -fn rewrite_pat_expr( - context: &RewriteContext, - pat: Option<&ast::Pat>, - expr: &ast::Expr, - matcher: &str, - // Connecting piece between pattern and expression, - // *without* trailing space. - connector: &str, - keyword: &str, - shape: Shape, - offset: usize, -) -> Option<String> { - debug!("rewrite_pat_expr {:?} {:?} {:?}", shape, pat, expr); - let cond_shape = shape.offset_left(offset)?; - if let Some(pat) = pat { - let matcher = if matcher.is_empty() { - matcher.to_owned() - } else { - format!("{} ", matcher) - }; - let pat_shape = cond_shape - .offset_left(matcher.len())? - .sub_width(connector.len())?; - let pat_string = pat.rewrite(context, pat_shape)?; - let result = format!("{}{}{}", matcher, pat_string, connector); - return rewrite_assign_rhs(context, result, expr, cond_shape); - } - - let expr_rw = expr.rewrite(context, cond_shape); - // The expression may (partially) fit on the current line. - // We do not allow splitting between `if` and condition. - if keyword == "if" || expr_rw.is_some() { - return expr_rw; - } - - // The expression won't fit on the current line, jump to next. - let nested_shape = shape - .block_indent(context.config.tab_spaces()) - .with_max_width(context.config); - let nested_indent_str = nested_shape.indent.to_string(context.config); - expr.rewrite(context, nested_shape) - .map(|expr_rw| format!("\n{}{}", nested_indent_str, expr_rw)) -} - -fn can_extend_match_arm_body(body: &ast::Expr) -> bool { - match body.node { - // We do not allow `if` to stay on the same line, since we could easily mistake - // `pat => if cond { ... }` and `pat if cond => { ... }`. - ast::ExprKind::If(..) | ast::ExprKind::IfLet(..) => false, - ast::ExprKind::ForLoop(..) - | ast::ExprKind::Loop(..) - | ast::ExprKind::While(..) - | ast::ExprKind::WhileLet(..) - | ast::ExprKind::Match(..) - | ast::ExprKind::Block(..) - | ast::ExprKind::Closure(..) - | ast::ExprKind::Array(..) - | ast::ExprKind::Call(..) - | ast::ExprKind::MethodCall(..) - | ast::ExprKind::Mac(..) - | ast::ExprKind::Struct(..) - | ast::ExprKind::Tup(..) => true, - ast::ExprKind::AddrOf(_, ref expr) - | ast::ExprKind::Box(ref expr) - | ast::ExprKind::Try(ref expr) - | ast::ExprKind::Unary(_, ref expr) - | ast::ExprKind::Cast(ref expr, _) => can_extend_match_arm_body(expr), - _ => false, - } -} - -pub fn rewrite_literal(context: &RewriteContext, l: &ast::Lit, shape: Shape) -> Option<String> { - match l.node { - ast::LitKind::Str(_, ast::StrStyle::Cooked) => rewrite_string_lit(context, l.span, shape), - _ => wrap_str( - context.snippet(l.span).to_owned(), - context.config.max_width(), - shape, - ), - } -} - -fn rewrite_string_lit(context: &RewriteContext, span: Span, shape: Shape) -> Option<String> { - let string_lit = context.snippet(span); - - if !context.config.format_strings() { - if string_lit - .lines() - .rev() - .skip(1) - .all(|line| line.ends_with('\\')) - { - let new_indent = shape.visual_indent(1).indent; - let indented_string_lit = String::from( - string_lit - .lines() - .map(|line| { - format!( - "{}{}", - new_indent.to_string(context.config), - line.trim_left() - ) - }) - .collect::<Vec<_>>() - .join("\n") - .trim_left(), - ); - return wrap_str(indented_string_lit, context.config.max_width(), shape); - } else { - return wrap_str(string_lit.to_owned(), context.config.max_width(), shape); - } - } - - // Remove the quote characters. - let str_lit = &string_lit[1..string_lit.len() - 1]; - - rewrite_string( - str_lit, - &StringFormat::new(shape.visual_indent(0), context.config), - None, - ) -} - -/// A list of `format!`-like macros, that take a long format string and a list of arguments to -/// format. -/// -/// Organized as a list of `(&str, usize)` tuples, giving the name of the macro and the number of -/// arguments before the format string (none for `format!("format", ...)`, one for `assert!(result, -/// "format", ...)`, two for `assert_eq!(left, right, "format", ...)`). -const SPECIAL_MACRO_WHITELIST: &[(&str, usize)] = &[ - // format! like macros - // From the Rust Standard Library. - ("eprint!", 0), - ("eprintln!", 0), - ("format!", 0), - ("format_args!", 0), - ("print!", 0), - ("println!", 0), - ("panic!", 0), - ("unreachable!", 0), - // From the `log` crate. - ("debug!", 0), - ("error!", 0), - ("info!", 0), - ("warn!", 0), - // write! like macros - ("assert!", 1), - ("debug_assert!", 1), - ("write!", 1), - ("writeln!", 1), - // assert_eq! like macros - ("assert_eq!", 2), - ("assert_ne!", 2), - ("debug_assert_eq!", 2), - ("debug_assert_ne!", 2), -]; - -pub fn rewrite_call( - context: &RewriteContext, - callee: &str, - args: &[ptr::P<ast::Expr>], - span: Span, - shape: Shape, -) -> Option<String> { - let force_trailing_comma = if context.inside_macro { - span_ends_with_comma(context, span) - } else { - false - }; - rewrite_call_inner( - context, - callee, - &ptr_vec_to_ref_vec(args), - span, - shape, - context.config.width_heuristics().fn_call_width, - force_trailing_comma, - ) -} - -pub fn rewrite_call_inner<'a, T>( - context: &RewriteContext, - callee_str: &str, - args: &[&T], - span: Span, - shape: Shape, - args_max_width: usize, - force_trailing_comma: bool, -) -> Option<String> -where - T: Rewrite + Spanned + ToExpr + 'a, -{ - // 2 = `( `, 1 = `(` - let paren_overhead = if context.config.spaces_within_parens_and_brackets() { - 2 - } else { - 1 - }; - let used_width = extra_offset(callee_str, shape); - let one_line_width = shape.width.checked_sub(used_width + 2 * paren_overhead)?; - - // 1 = "(" or ")" - let one_line_shape = shape - .offset_left(last_line_width(callee_str) + 1)? - .sub_width(1)?; - let nested_shape = shape_from_indent_style( - context, - shape, - used_width + 2 * paren_overhead, - used_width + paren_overhead, - )?; - - let span_lo = context.codemap.span_after(span, "("); - let args_span = mk_sp(span_lo, span.hi()); - - let (extendable, list_str) = rewrite_call_args( - context, - args, - args_span, - one_line_shape, - nested_shape, - one_line_width, - args_max_width, - force_trailing_comma, - callee_str, - )?; - - if !context.use_block_indent() && need_block_indent(&list_str, nested_shape) && !extendable { - let mut new_context = context.clone(); - new_context.use_block = true; - return rewrite_call_inner( - &new_context, - callee_str, - args, - span, - shape, - args_max_width, - force_trailing_comma, - ); - } - - let args_shape = shape.sub_width(last_line_width(callee_str))?; - Some(format!( - "{}{}", - callee_str, - wrap_args_with_parens(context, &list_str, extendable, args_shape, nested_shape) - )) -} - -fn need_block_indent(s: &str, shape: Shape) -> bool { - s.lines().skip(1).any(|s| { - s.find(|c| !char::is_whitespace(c)) - .map_or(false, |w| w + 1 < shape.indent.width()) - }) -} - -fn rewrite_call_args<'a, T>( - context: &RewriteContext, - args: &[&T], - span: Span, - one_line_shape: Shape, - nested_shape: Shape, - one_line_width: usize, - args_max_width: usize, - force_trailing_comma: bool, - callee_str: &str, -) -> Option<(bool, String)> -where - T: Rewrite + Spanned + ToExpr + 'a, -{ - let items = itemize_list( - context.codemap, - args.iter(), - ")", - ",", - |item| item.span().lo(), - |item| item.span().hi(), - |item| item.rewrite(context, nested_shape), - span.lo(), - span.hi(), - true, - ); - let mut item_vec: Vec<_> = items.collect(); - - // Try letting the last argument overflow to the next line with block - // indentation. If its first line fits on one line with the other arguments, - // we format the function arguments horizontally. - let tactic = try_overflow_last_arg( - context, - &mut item_vec, - &args[..], - one_line_shape, - nested_shape, - one_line_width, - args_max_width, - callee_str, - ); - - let fmt = ListFormatting { - tactic, - separator: ",", - trailing_separator: if force_trailing_comma { - SeparatorTactic::Always - } else if context.inside_macro || !context.use_block_indent() { - SeparatorTactic::Never - } else { - context.config.trailing_comma() - }, - separator_place: SeparatorPlace::Back, - shape: nested_shape, - ends_with_newline: context.use_block_indent() && tactic == DefinitiveListTactic::Vertical, - preserve_newline: false, - config: context.config, - }; - - write_list(&item_vec, &fmt) - .map(|args_str| (tactic == DefinitiveListTactic::Horizontal, args_str)) -} - -fn try_overflow_last_arg<'a, T>( - context: &RewriteContext, - item_vec: &mut Vec<ListItem>, - args: &[&T], - one_line_shape: Shape, - nested_shape: Shape, - one_line_width: usize, - args_max_width: usize, - callee_str: &str, -) -> DefinitiveListTactic -where - T: Rewrite + Spanned + ToExpr + 'a, -{ - // 1 = "(" - let combine_arg_with_callee = - callee_str.len() + 1 <= context.config.tab_spaces() && args.len() == 1; - let overflow_last = combine_arg_with_callee || can_be_overflowed(context, args); - - // Replace the last item with its first line to see if it fits with - // first arguments. - let placeholder = if overflow_last { - let mut context = context.clone(); - if !combine_arg_with_callee { - if let Some(expr) = args[args.len() - 1].to_expr() { - if let ast::ExprKind::MethodCall(..) = expr.node { - context.force_one_line_chain = true; - } - } - } - last_arg_shape(args, item_vec, one_line_shape, args_max_width).and_then(|arg_shape| { - rewrite_last_arg_with_overflow(&context, args, &mut item_vec[args.len() - 1], arg_shape) - }) - } else { - None - }; - - let mut tactic = definitive_tactic( - &*item_vec, - ListTactic::LimitedHorizontalVertical(args_max_width), - Separator::Comma, - one_line_width, - ); - - // Replace the stub with the full overflowing last argument if the rewrite - // succeeded and its first line fits with the other arguments. - match (overflow_last, tactic, placeholder) { - (true, DefinitiveListTactic::Horizontal, Some(ref overflowed)) if args.len() == 1 => { - // When we are rewriting a nested function call, we restrict the - // bugdet for the inner function to avoid them being deeply nested. - // However, when the inner function has a prefix or a suffix - // (e.g. `foo() as u32`), this budget reduction may produce poorly - // formatted code, where a prefix or a suffix being left on its own - // line. Here we explicitlly check those cases. - if count_newlines(overflowed) == 1 { - let rw = args.last() - .and_then(|last_arg| last_arg.rewrite(context, nested_shape)); - let no_newline = rw.as_ref().map_or(false, |s| !s.contains('\n')); - if no_newline { - item_vec[args.len() - 1].item = rw; - } else { - item_vec[args.len() - 1].item = Some(overflowed.to_owned()); - } - } else { - item_vec[args.len() - 1].item = Some(overflowed.to_owned()); - } - } - (true, DefinitiveListTactic::Horizontal, placeholder @ Some(..)) => { - item_vec[args.len() - 1].item = placeholder; - } - _ if args.len() >= 1 => { - item_vec[args.len() - 1].item = args.last() - .and_then(|last_arg| last_arg.rewrite(context, nested_shape)); - - let default_tactic = || { - definitive_tactic( - &*item_vec, - ListTactic::LimitedHorizontalVertical(args_max_width), - Separator::Comma, - one_line_width, - ) - }; - - // Use horizontal layout for a function with a single argument as long as - // everything fits in a single line. - if args.len() == 1 - && args_max_width != 0 // Vertical layout is forced. - && !item_vec[0].has_comment() - && !item_vec[0].inner_as_ref().contains('\n') - && ::lists::total_item_width(&item_vec[0]) <= one_line_width - { - tactic = DefinitiveListTactic::Horizontal; - } else { - tactic = default_tactic(); - - if tactic == DefinitiveListTactic::Vertical { - if let Some((all_simple, num_args_before)) = - maybe_get_args_offset(callee_str, args) - { - let one_line = all_simple - && definitive_tactic( - &item_vec[..num_args_before], - ListTactic::HorizontalVertical, - Separator::Comma, - nested_shape.width, - ) == DefinitiveListTactic::Horizontal - && definitive_tactic( - &item_vec[num_args_before + 1..], - ListTactic::HorizontalVertical, - Separator::Comma, - nested_shape.width, - ) == DefinitiveListTactic::Horizontal; - - if one_line { - tactic = DefinitiveListTactic::SpecialMacro(num_args_before); - }; - } - } - } - } - _ => (), - } - - tactic -} - -fn is_simple_arg(expr: &ast::Expr) -> bool { - match expr.node { - ast::ExprKind::Lit(..) => true, - ast::ExprKind::Path(ref qself, ref path) => qself.is_none() && path.segments.len() <= 1, - ast::ExprKind::AddrOf(_, ref expr) - | ast::ExprKind::Box(ref expr) - | ast::ExprKind::Cast(ref expr, _) - | ast::ExprKind::Field(ref expr, _) - | ast::ExprKind::Try(ref expr) - | ast::ExprKind::TupField(ref expr, _) - | ast::ExprKind::Unary(_, ref expr) => is_simple_arg(expr), - ast::ExprKind::Index(ref lhs, ref rhs) | ast::ExprKind::Repeat(ref lhs, ref rhs) => { - is_simple_arg(lhs) && is_simple_arg(rhs) - } - _ => false, - } -} - -fn is_every_args_simple<T: ToExpr>(lists: &[&T]) -> bool { - lists - .iter() - .all(|arg| arg.to_expr().map_or(false, is_simple_arg)) -} - -/// In case special-case style is required, returns an offset from which we start horizontal layout. -fn maybe_get_args_offset<T: ToExpr>(callee_str: &str, args: &[&T]) -> Option<(bool, usize)> { - if let Some(&(_, num_args_before)) = SPECIAL_MACRO_WHITELIST - .iter() - .find(|&&(s, _)| s == callee_str) - { - let all_simple = args.len() > num_args_before && is_every_args_simple(args); - - Some((all_simple, num_args_before)) - } else { - None - } -} - -/// Returns a shape for the last argument which is going to be overflowed. -fn last_arg_shape<T>( - lists: &[&T], - items: &[ListItem], - shape: Shape, - args_max_width: usize, -) -> Option<Shape> -where - T: Rewrite + Spanned + ToExpr, -{ - let is_nested_call = lists - .iter() - .next() - .and_then(|item| item.to_expr()) - .map_or(false, is_nested_call); - if items.len() == 1 && !is_nested_call { - return Some(shape); - } - let offset = items.iter().rev().skip(1).fold(0, |acc, i| { - // 2 = ", " - acc + 2 + i.inner_as_ref().len() - }); - Shape { - width: min(args_max_width, shape.width), - ..shape - }.offset_left(offset) -} - -fn rewrite_last_arg_with_overflow<'a, T>( - context: &RewriteContext, - args: &[&T], - last_item: &mut ListItem, - shape: Shape, -) -> Option<String> -where - T: Rewrite + Spanned + ToExpr + 'a, -{ - let last_arg = args[args.len() - 1]; - let rewrite = if let Some(expr) = last_arg.to_expr() { - match expr.node { - // When overflowing the closure which consists of a single control flow expression, - // force to use block if its condition uses multi line. - ast::ExprKind::Closure(..) => { - // If the argument consists of multiple closures, we do not overflow - // the last closure. - if closures::args_have_many_closure(args) { - None - } else { - closures::rewrite_last_closure(context, expr, shape) - } - } - _ => expr.rewrite(context, shape), - } - } else { - last_arg.rewrite(context, shape) - }; - - if let Some(rewrite) = rewrite { - let rewrite_first_line = Some(rewrite[..first_line_width(&rewrite)].to_owned()); - last_item.item = rewrite_first_line; - Some(rewrite) - } else { - None - } -} - -fn can_be_overflowed<'a, T>(context: &RewriteContext, args: &[&T]) -> bool -where - T: Rewrite + Spanned + ToExpr + 'a, -{ - args.last() - .map_or(false, |x| x.can_be_overflowed(context, args.len())) -} - -pub fn can_be_overflowed_expr(context: &RewriteContext, expr: &ast::Expr, args_len: usize) -> bool { - match expr.node { - ast::ExprKind::Match(..) => { - (context.use_block_indent() && args_len == 1) - || (context.config.indent_style() == IndentStyle::Visual && args_len > 1) - } - ast::ExprKind::If(..) - | ast::ExprKind::IfLet(..) - | ast::ExprKind::ForLoop(..) - | ast::ExprKind::Loop(..) - | ast::ExprKind::While(..) - | ast::ExprKind::WhileLet(..) => { - context.config.combine_control_expr() && context.use_block_indent() && args_len == 1 - } - ast::ExprKind::Block(..) | ast::ExprKind::Closure(..) => { - context.use_block_indent() - || context.config.indent_style() == IndentStyle::Visual && args_len > 1 - } - ast::ExprKind::Array(..) - | ast::ExprKind::Call(..) - | ast::ExprKind::Mac(..) - | ast::ExprKind::MethodCall(..) - | ast::ExprKind::Struct(..) - | ast::ExprKind::Tup(..) => context.use_block_indent() && args_len == 1, - ast::ExprKind::AddrOf(_, ref expr) - | ast::ExprKind::Box(ref expr) - | ast::ExprKind::Try(ref expr) - | ast::ExprKind::Unary(_, ref expr) - | ast::ExprKind::Cast(ref expr, _) => can_be_overflowed_expr(context, expr, args_len), - _ => false, - } -} - -fn is_nested_call(expr: &ast::Expr) -> bool { - match expr.node { - ast::ExprKind::Call(..) | ast::ExprKind::Mac(..) => true, - ast::ExprKind::AddrOf(_, ref expr) - | ast::ExprKind::Box(ref expr) - | ast::ExprKind::Try(ref expr) - | ast::ExprKind::Unary(_, ref expr) - | ast::ExprKind::Cast(ref expr, _) => is_nested_call(expr), - _ => false, - } -} - -pub fn wrap_args_with_parens( - context: &RewriteContext, - args_str: &str, - is_extendable: bool, - shape: Shape, - nested_shape: Shape, -) -> String { - if !context.use_block_indent() - || (context.inside_macro && !args_str.contains('\n') - && args_str.len() + paren_overhead(context) <= shape.width) || is_extendable - { - if context.config.spaces_within_parens_and_brackets() && !args_str.is_empty() { - format!("( {} )", args_str) - } else { - format!("({})", args_str) - } - } else { - format!( - "(\n{}{}\n{})", - nested_shape.indent.to_string(context.config), - args_str, - shape.block().indent.to_string(context.config) - ) - } -} - -/// Return true if a function call or a method call represented by the given span ends with a -/// trailing comma. This function is used when rewriting macro, as adding or removing a trailing -/// comma from macro can potentially break the code. -fn span_ends_with_comma(context: &RewriteContext, span: Span) -> bool { - let mut encountered_closing_paren = false; - for c in context.snippet(span).chars().rev() { - match c { - ',' => return true, - ')' => if encountered_closing_paren { - return false; - } else { - encountered_closing_paren = true; - }, - _ if c.is_whitespace() => continue, - _ => return false, - } - } - false -} - -fn rewrite_paren(context: &RewriteContext, subexpr: &ast::Expr, shape: Shape) -> Option<String> { - debug!("rewrite_paren, shape: {:?}", shape); - let total_paren_overhead = paren_overhead(context); - let paren_overhead = total_paren_overhead / 2; - let sub_shape = shape - .offset_left(paren_overhead) - .and_then(|s| s.sub_width(paren_overhead))?; - - let paren_wrapper = |s: &str| { - if context.config.spaces_within_parens_and_brackets() && !s.is_empty() { - format!("( {} )", s) - } else { - format!("({})", s) - } - }; - - let subexpr_str = subexpr.rewrite(context, sub_shape)?; - debug!("rewrite_paren, subexpr_str: `{:?}`", subexpr_str); - - if subexpr_str.contains('\n') - || first_line_width(&subexpr_str) + total_paren_overhead <= shape.width - { - Some(paren_wrapper(&subexpr_str)) - } else { - None - } -} - -fn rewrite_index( - expr: &ast::Expr, - index: &ast::Expr, - context: &RewriteContext, - shape: Shape, -) -> Option<String> { - let expr_str = expr.rewrite(context, shape)?; - - let (lbr, rbr) = if context.config.spaces_within_parens_and_brackets() { - ("[ ", " ]") - } else { - ("[", "]") - }; - - let offset = last_line_width(&expr_str) + lbr.len(); - let rhs_overhead = shape.rhs_overhead(context.config); - let index_shape = if expr_str.contains('\n') { - Shape::legacy(context.config.max_width(), shape.indent) - .offset_left(offset) - .and_then(|shape| shape.sub_width(rbr.len() + rhs_overhead)) - } else { - shape.visual_indent(offset).sub_width(offset + rbr.len()) - }; - let orig_index_rw = index_shape.and_then(|s| index.rewrite(context, s)); - - // Return if index fits in a single line. - match orig_index_rw { - Some(ref index_str) if !index_str.contains('\n') => { - return Some(format!("{}{}{}{}", expr_str, lbr, index_str, rbr)); - } - _ => (), - } - - // Try putting index on the next line and see if it fits in a single line. - let indent = shape.indent.block_indent(context.config); - let index_shape = Shape::indented(indent, context.config).offset_left(lbr.len())?; - let index_shape = index_shape.sub_width(rbr.len() + rhs_overhead)?; - let new_index_rw = index.rewrite(context, index_shape); - match (orig_index_rw, new_index_rw) { - (_, Some(ref new_index_str)) if !new_index_str.contains('\n') => Some(format!( - "{}\n{}{}{}{}", - expr_str, - indent.to_string(context.config), - lbr, - new_index_str, - rbr - )), - (None, Some(ref new_index_str)) => Some(format!( - "{}\n{}{}{}{}", - expr_str, - indent.to_string(context.config), - lbr, - new_index_str, - rbr - )), - (Some(ref index_str), _) => Some(format!("{}{}{}{}", expr_str, lbr, index_str, rbr)), - _ => None, - } -} - -fn struct_lit_can_be_aligned(fields: &[ast::Field], base: &Option<&ast::Expr>) -> bool { - if base.is_some() { - return false; - } - - fields.iter().all(|field| !field.is_shorthand) -} - -fn rewrite_struct_lit<'a>( - context: &RewriteContext, - path: &ast::Path, - fields: &'a [ast::Field], - base: Option<&'a ast::Expr>, - span: Span, - shape: Shape, -) -> Option<String> { - debug!("rewrite_struct_lit: shape {:?}", shape); - - enum StructLitField<'a> { - Regular(&'a ast::Field), - Base(&'a ast::Expr), - } - - // 2 = " {".len() - let path_shape = shape.sub_width(2)?; - let path_str = rewrite_path(context, PathContext::Expr, None, path, path_shape)?; - - if fields.is_empty() && base.is_none() { - return Some(format!("{} {{}}", path_str)); - } - - // Foo { a: Foo } - indent is +3, width is -5. - let (h_shape, v_shape) = struct_lit_shape(shape, context, path_str.len() + 3, 2)?; - - let one_line_width = h_shape.map_or(0, |shape| shape.width); - let body_lo = context.codemap.span_after(span, "{"); - let fields_str = if struct_lit_can_be_aligned(fields, &base) - && context.config.struct_field_align_threshold() > 0 - { - rewrite_with_alignment( - fields, - context, - shape, - mk_sp(body_lo, span.hi()), - one_line_width, - )? - } else { - let field_iter = fields - .into_iter() - .map(StructLitField::Regular) - .chain(base.into_iter().map(StructLitField::Base)); - - let span_lo = |item: &StructLitField| match *item { - StructLitField::Regular(field) => field.span().lo(), - StructLitField::Base(expr) => { - let last_field_hi = fields.last().map_or(span.lo(), |field| field.span.hi()); - let snippet = context.snippet(mk_sp(last_field_hi, expr.span.lo())); - let pos = snippet.find_uncommented("..").unwrap(); - last_field_hi + BytePos(pos as u32) - } - }; - let span_hi = |item: &StructLitField| match *item { - StructLitField::Regular(field) => field.span().hi(), - StructLitField::Base(expr) => expr.span.hi(), - }; - let rewrite = |item: &StructLitField| match *item { - StructLitField::Regular(field) => { - // The 1 taken from the v_budget is for the comma. - rewrite_field(context, field, v_shape.sub_width(1)?, 0) - } - StructLitField::Base(expr) => { - // 2 = .. - expr.rewrite(context, v_shape.offset_left(2)?) - .map(|s| format!("..{}", s)) - } - }; - - let items = itemize_list( - context.codemap, - field_iter, - "}", - ",", - span_lo, - span_hi, - rewrite, - body_lo, - span.hi(), - false, - ); - let item_vec = items.collect::<Vec<_>>(); - - let tactic = struct_lit_tactic(h_shape, context, &item_vec); - let nested_shape = shape_for_tactic(tactic, h_shape, v_shape); - let fmt = struct_lit_formatting(nested_shape, tactic, context, base.is_some()); - - write_list(&item_vec, &fmt)? - }; - - let fields_str = wrap_struct_field(context, &fields_str, shape, v_shape, one_line_width); - Some(format!("{} {{{}}}", path_str, fields_str)) - - // FIXME if context.config.indent_style() == Visual, but we run out - // of space, we should fall back to BlockIndent. -} - -pub fn wrap_struct_field( - context: &RewriteContext, - fields_str: &str, - shape: Shape, - nested_shape: Shape, - one_line_width: usize, -) -> String { - if context.config.indent_style() == IndentStyle::Block - && (fields_str.contains('\n') || !context.config.struct_lit_single_line() - || fields_str.len() > one_line_width) - { - format!( - "\n{}{}\n{}", - nested_shape.indent.to_string(context.config), - fields_str, - shape.indent.to_string(context.config) - ) - } else { - // One liner or visual indent. - format!(" {} ", fields_str) - } -} - -pub fn struct_lit_field_separator(config: &Config) -> &str { - colon_spaces(config.space_before_colon(), config.space_after_colon()) -} - -pub fn rewrite_field( - context: &RewriteContext, - field: &ast::Field, - shape: Shape, - prefix_max_width: usize, -) -> Option<String> { - if contains_skip(&field.attrs) { - return Some(context.snippet(field.span()).to_owned()); - } - let mut attrs_str = field.attrs.rewrite(context, shape)?; - if !attrs_str.is_empty() { - attrs_str.push_str(&format!("\n{}", shape.indent.to_string(context.config))); - }; - let name = field.ident.node.to_string(); - if field.is_shorthand { - Some(attrs_str + &name) - } else { - let mut separator = String::from(struct_lit_field_separator(context.config)); - for _ in 0..prefix_max_width.checked_sub(name.len()).unwrap_or(0) { - separator.push(' '); - } - let overhead = name.len() + separator.len(); - let expr_shape = shape.offset_left(overhead)?; - let expr = field.expr.rewrite(context, expr_shape); - - match expr { - Some(ref e) if e.as_str() == name && context.config.use_field_init_shorthand() => { - Some(attrs_str + &name) - } - Some(e) => Some(format!("{}{}{}{}", attrs_str, name, separator, e)), - None => { - let expr_offset = shape.indent.block_indent(context.config); - let expr = field - .expr - .rewrite(context, Shape::indented(expr_offset, context.config)); - expr.map(|s| { - format!( - "{}{}:\n{}{}", - attrs_str, - name, - expr_offset.to_string(context.config), - s - ) - }) - } - } - } -} - -fn shape_from_indent_style( - context: &RewriteContext, - shape: Shape, - overhead: usize, - offset: usize, -) -> Option<Shape> { - if context.use_block_indent() { - // 1 = "," - shape - .block() - .block_indent(context.config.tab_spaces()) - .with_max_width(context.config) - .sub_width(1) - } else { - shape.visual_indent(offset).sub_width(overhead) - } -} - -fn rewrite_tuple_in_visual_indent_style<'a, T>( - context: &RewriteContext, - items: &[&T], - span: Span, - shape: Shape, -) -> Option<String> -where - T: Rewrite + Spanned + ToExpr + 'a, -{ - let mut items = items.iter(); - // In case of length 1, need a trailing comma - debug!("rewrite_tuple_in_visual_indent_style {:?}", shape); - if items.len() == 1 { - // 3 = "(" + ",)" - let nested_shape = shape.sub_width(3)?.visual_indent(1); - return items - .next() - .unwrap() - .rewrite(context, nested_shape) - .map(|s| { - if context.config.spaces_within_parens_and_brackets() { - format!("( {}, )", s) - } else { - format!("({},)", s) - } - }); - } - - let list_lo = context.codemap.span_after(span, "("); - let nested_shape = shape.sub_width(2)?.visual_indent(1); - let items = itemize_list( - context.codemap, - items, - ")", - ",", - |item| item.span().lo(), - |item| item.span().hi(), - |item| item.rewrite(context, nested_shape), - list_lo, - span.hi() - BytePos(1), - false, - ); - let item_vec: Vec<_> = items.collect(); - let tactic = definitive_tactic( - &item_vec, - ListTactic::HorizontalVertical, - Separator::Comma, - nested_shape.width, - ); - let fmt = ListFormatting { - tactic, - separator: ",", - trailing_separator: SeparatorTactic::Never, - separator_place: SeparatorPlace::Back, - shape, - ends_with_newline: false, - preserve_newline: false, - config: context.config, - }; - let list_str = write_list(&item_vec, &fmt)?; - - if context.config.spaces_within_parens_and_brackets() && !list_str.is_empty() { - Some(format!("( {} )", list_str)) - } else { - Some(format!("({})", list_str)) - } -} - -pub fn rewrite_tuple<'a, T>( - context: &RewriteContext, - items: &[&T], - span: Span, - shape: Shape, -) -> Option<String> -where - T: Rewrite + Spanned + ToExpr + 'a, -{ - debug!("rewrite_tuple {:?}", shape); - if context.use_block_indent() { - // We use the same rule as function calls for rewriting tuples. - let force_trailing_comma = if context.inside_macro { - span_ends_with_comma(context, span) - } else { - items.len() == 1 - }; - rewrite_call_inner( - context, - &String::new(), - items, - span, - shape, - context.config.width_heuristics().fn_call_width, - force_trailing_comma, - ) - } else { - rewrite_tuple_in_visual_indent_style(context, items, span, shape) - } -} - -pub fn rewrite_unary_prefix<R: Rewrite>( - context: &RewriteContext, - prefix: &str, - rewrite: &R, - shape: Shape, -) -> Option<String> { - rewrite - .rewrite(context, shape.offset_left(prefix.len())?) - .map(|r| format!("{}{}", prefix, r)) -} - -// FIXME: this is probably not correct for multi-line Rewrites. we should -// subtract suffix.len() from the last line budget, not the first! -pub fn rewrite_unary_suffix<R: Rewrite>( - context: &RewriteContext, - suffix: &str, - rewrite: &R, - shape: Shape, -) -> Option<String> { - rewrite - .rewrite(context, shape.sub_width(suffix.len())?) - .map(|mut r| { - r.push_str(suffix); - r - }) -} - -fn rewrite_unary_op( - context: &RewriteContext, - op: &ast::UnOp, - expr: &ast::Expr, - shape: Shape, -) -> Option<String> { - // For some reason, an UnOp is not spanned like BinOp! - let operator_str = match *op { - ast::UnOp::Deref => "*", - ast::UnOp::Not => "!", - ast::UnOp::Neg => "-", - }; - rewrite_unary_prefix(context, operator_str, expr, shape) -} - -fn rewrite_assignment( - context: &RewriteContext, - lhs: &ast::Expr, - rhs: &ast::Expr, - op: Option<&ast::BinOp>, - shape: Shape, -) -> Option<String> { - let operator_str = match op { - Some(op) => context.snippet(op.span), - None => "=", - }; - - // 1 = space between lhs and operator. - let lhs_shape = shape.sub_width(operator_str.len() + 1)?; - let lhs_str = format!("{} {}", lhs.rewrite(context, lhs_shape)?, operator_str); - - rewrite_assign_rhs(context, lhs_str, rhs, shape) -} - -// The left hand side must contain everything up to, and including, the -// assignment operator. -pub fn rewrite_assign_rhs<S: Into<String>, R: Rewrite>( - context: &RewriteContext, - lhs: S, - ex: &R, - shape: Shape, -) -> Option<String> { - let lhs = lhs.into(); - let last_line_width = last_line_width(&lhs) - .checked_sub(if lhs.contains('\n') { - shape.indent.width() - } else { - 0 - }) - .unwrap_or(0); - // 1 = space between operator and rhs. - let orig_shape = shape.offset_left(last_line_width + 1).unwrap_or(Shape { - width: 0, - offset: shape.offset + last_line_width + 1, - ..shape - }); - let rhs = choose_rhs(context, ex, orig_shape, ex.rewrite(context, orig_shape))?; - Some(lhs + &rhs) -} - -pub fn choose_rhs<R: Rewrite>( - context: &RewriteContext, - expr: &R, - shape: Shape, - orig_rhs: Option<String>, -) -> Option<String> { - match orig_rhs { - Some(ref new_str) if !new_str.contains('\n') && new_str.len() <= shape.width => { - Some(format!(" {}", new_str)) - } - _ => { - // Expression did not fit on the same line as the identifier. - // Try splitting the line and see if that works better. - let new_shape = - Shape::indented(shape.indent.block_indent(context.config), context.config) - .sub_width(shape.rhs_overhead(context.config))?; - let new_rhs = expr.rewrite(context, new_shape); - let new_indent_str = &new_shape.indent.to_string(context.config); - - match (orig_rhs, new_rhs) { - (Some(ref orig_rhs), Some(ref new_rhs)) - if wrap_str(new_rhs.clone(), context.config.max_width(), new_shape) - .is_none() => - { - Some(format!(" {}", orig_rhs)) - } - (Some(ref orig_rhs), Some(ref new_rhs)) if prefer_next_line(orig_rhs, new_rhs) => { - Some(format!("\n{}{}", new_indent_str, new_rhs)) - } - (None, Some(ref new_rhs)) => Some(format!("\n{}{}", new_indent_str, new_rhs)), - (None, None) => None, - (Some(ref orig_rhs), _) => Some(format!(" {}", orig_rhs)), - } - } - } -} - -fn prefer_next_line(orig_rhs: &str, next_line_rhs: &str) -> bool { - !next_line_rhs.contains('\n') || count_newlines(orig_rhs) > count_newlines(next_line_rhs) + 1 -} - -fn rewrite_expr_addrof( - context: &RewriteContext, - mutability: ast::Mutability, - expr: &ast::Expr, - shape: Shape, -) -> Option<String> { - let operator_str = match mutability { - ast::Mutability::Immutable => "&", - ast::Mutability::Mutable => "&mut ", - }; - rewrite_unary_prefix(context, operator_str, expr, shape) -} - -pub trait ToExpr { - fn to_expr(&self) -> Option<&ast::Expr>; - fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool; -} - -impl ToExpr for ast::Expr { - fn to_expr(&self) -> Option<&ast::Expr> { - Some(self) - } - - fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool { - can_be_overflowed_expr(context, self, len) - } -} - -impl ToExpr for ast::Ty { - fn to_expr(&self) -> Option<&ast::Expr> { - None - } - - fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool { - can_be_overflowed_type(context, self, len) - } -} - -impl<'a> ToExpr for TuplePatField<'a> { - fn to_expr(&self) -> Option<&ast::Expr> { - None - } - - fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool { - can_be_overflowed_pat(context, self, len) - } -} - -impl<'a> ToExpr for ast::StructField { - fn to_expr(&self) -> Option<&ast::Expr> { - None - } - - fn can_be_overflowed(&self, _: &RewriteContext, _: usize) -> bool { - false - } -} - -impl<'a> ToExpr for MacroArg { - fn to_expr(&self) -> Option<&ast::Expr> { - match *self { - MacroArg::Expr(ref expr) => Some(expr), - _ => None, - } - } - - fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool { - match *self { - MacroArg::Expr(ref expr) => can_be_overflowed_expr(context, expr, len), - MacroArg::Ty(ref ty) => can_be_overflowed_type(context, ty, len), - MacroArg::Pat(..) => false, - } - } -} |