2317 lines
88 KiB
Rust
2317 lines
88 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use std::cmp::{Ordering, min};
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use std::mem::swap;
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use std::ops::Deref;
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use std::iter::ExactSizeIterator;
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use std::fmt::Write;
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use {Indent, Shape, Spanned};
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use codemap::SpanUtils;
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use rewrite::{Rewrite, RewriteContext};
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use lists::{write_list, itemize_list, ListFormatting, SeparatorTactic, ListTactic,
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DefinitiveListTactic, definitive_tactic, ListItem, format_item_list, struct_lit_shape,
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struct_lit_tactic, shape_for_tactic, struct_lit_formatting};
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use string::{StringFormat, rewrite_string};
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use utils::{extra_offset, last_line_width, wrap_str, binary_search, first_line_width,
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semicolon_for_stmt, trimmed_last_line_width, left_most_sub_expr, stmt_expr,
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colon_spaces, contains_skip};
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use visitor::FmtVisitor;
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use config::{Config, IndentStyle, MultilineStyle, ControlBraceStyle, Style};
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use comment::{FindUncommented, rewrite_comment, contains_comment, recover_comment_removed};
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use types::{rewrite_path, PathContext};
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use items::{span_lo_for_arg, span_hi_for_arg};
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use chains::rewrite_chain;
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use macros::{rewrite_macro, MacroPosition};
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use syntax::{ast, ptr};
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use syntax::codemap::{CodeMap, Span, BytePos, mk_sp};
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use syntax::parse::classify;
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impl Rewrite for ast::Expr {
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fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
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format_expr(self, ExprType::SubExpression, context, shape)
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}
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}
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#[derive(PartialEq)]
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enum ExprType {
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Statement,
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SubExpression,
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}
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fn format_expr(expr: &ast::Expr,
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expr_type: ExprType,
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context: &RewriteContext,
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shape: Shape)
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-> Option<String> {
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if contains_skip(&*expr.attrs) {
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return Some(context.snippet(expr.span));
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}
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let attr_rw = (&*expr.attrs).rewrite(context, shape);
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let expr_rw = match expr.node {
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ast::ExprKind::Array(ref expr_vec) => {
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rewrite_array(expr_vec.iter().map(|e| &**e),
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mk_sp(context.codemap.span_after(expr.span, "["), expr.span.hi),
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context,
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shape)
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}
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ast::ExprKind::Lit(ref l) => {
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match l.node {
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ast::LitKind::Str(_, ast::StrStyle::Cooked) => {
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rewrite_string_lit(context, l.span, shape)
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}
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_ => {
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wrap_str(context.snippet(expr.span),
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context.config.max_width(),
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shape)
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}
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}
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}
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ast::ExprKind::Call(ref callee, ref args) => {
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let inner_span = mk_sp(callee.span.hi, expr.span.hi);
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rewrite_call_with_binary_search(context, &**callee, args, inner_span, shape)
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}
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ast::ExprKind::Paren(ref subexpr) => rewrite_paren(context, subexpr, shape),
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ast::ExprKind::Binary(ref op, ref lhs, ref rhs) => {
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// FIXME: format comments between operands and operator
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rewrite_pair(&**lhs,
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&**rhs,
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"",
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&format!(" {} ", context.snippet(op.span)),
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"",
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context,
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shape)
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}
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ast::ExprKind::Unary(ref op, ref subexpr) => rewrite_unary_op(context, op, subexpr, shape),
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ast::ExprKind::Struct(ref path, ref fields, ref base) => {
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rewrite_struct_lit(context,
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path,
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fields,
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base.as_ref().map(|e| &**e),
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expr.span,
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shape)
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}
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ast::ExprKind::Tup(ref items) => rewrite_tuple(context, items, expr.span, shape),
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ast::ExprKind::While(ref cond, ref block, label) => {
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ControlFlow::new_while(None, cond, block, label, expr.span).rewrite(context, shape)
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}
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ast::ExprKind::WhileLet(ref pat, ref cond, ref block, label) => {
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ControlFlow::new_while(Some(pat), cond, block, label, expr.span).rewrite(context, shape)
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}
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ast::ExprKind::ForLoop(ref pat, ref cond, ref block, label) => {
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ControlFlow::new_for(pat, cond, block, label, expr.span).rewrite(context, shape)
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}
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ast::ExprKind::Loop(ref block, label) => {
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ControlFlow::new_loop(block, label, expr.span).rewrite(context, shape)
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}
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ast::ExprKind::Block(ref block) => block.rewrite(context, shape),
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ast::ExprKind::If(ref cond, ref if_block, ref else_block) => {
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ControlFlow::new_if(cond,
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None,
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if_block,
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else_block.as_ref().map(|e| &**e),
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expr_type == ExprType::SubExpression,
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false,
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expr.span)
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.rewrite(context, shape)
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}
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ast::ExprKind::IfLet(ref pat, ref cond, ref if_block, ref else_block) => {
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ControlFlow::new_if(cond,
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Some(pat),
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if_block,
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else_block.as_ref().map(|e| &**e),
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expr_type == ExprType::SubExpression,
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false,
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expr.span)
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.rewrite(context, shape)
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}
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ast::ExprKind::Match(ref cond, ref arms) => {
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rewrite_match(context, cond, arms, shape, expr.span)
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}
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ast::ExprKind::Path(ref qself, ref path) => {
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rewrite_path(context, PathContext::Expr, qself.as_ref(), path, shape)
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}
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ast::ExprKind::Assign(ref lhs, ref rhs) => {
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rewrite_assignment(context, lhs, rhs, None, shape)
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}
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ast::ExprKind::AssignOp(ref op, ref lhs, ref rhs) => {
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rewrite_assignment(context, lhs, rhs, Some(op), shape)
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}
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ast::ExprKind::Continue(ref opt_ident) => {
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let id_str = match *opt_ident {
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Some(ident) => format!(" {}", ident.node),
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None => String::new(),
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};
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wrap_str(format!("continue{}", id_str),
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context.config.max_width(),
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shape)
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}
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ast::ExprKind::Break(ref opt_ident, ref opt_expr) => {
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let id_str = match *opt_ident {
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Some(ident) => format!(" {}", ident.node),
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None => String::new(),
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};
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if let Some(ref expr) = *opt_expr {
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rewrite_unary_prefix(context, &format!("break{} ", id_str), &**expr, shape)
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} else {
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wrap_str(format!("break{}", id_str),
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context.config.max_width(),
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shape)
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}
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}
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ast::ExprKind::Closure(capture, ref fn_decl, ref body, _) => {
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rewrite_closure(capture, fn_decl, body, expr.span, context, shape)
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}
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ast::ExprKind::Try(..) |
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ast::ExprKind::Field(..) |
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ast::ExprKind::TupField(..) |
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ast::ExprKind::MethodCall(..) => rewrite_chain(expr, context, shape),
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ast::ExprKind::Mac(ref mac) => {
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// Failure to rewrite a marco should not imply failure to
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// rewrite the expression.
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rewrite_macro(mac, None, context, shape, MacroPosition::Expression).or_else(|| {
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wrap_str(context.snippet(expr.span),
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context.config.max_width(),
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shape)
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})
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}
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ast::ExprKind::Ret(None) => {
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wrap_str("return".to_owned(), context.config.max_width(), shape)
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}
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ast::ExprKind::Ret(Some(ref expr)) => {
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rewrite_unary_prefix(context, "return ", &**expr, shape)
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}
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ast::ExprKind::Box(ref expr) => rewrite_unary_prefix(context, "box ", &**expr, shape),
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ast::ExprKind::AddrOf(mutability, ref expr) => {
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rewrite_expr_addrof(context, mutability, expr, shape)
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}
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ast::ExprKind::Cast(ref expr, ref ty) => {
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rewrite_pair(&**expr, &**ty, "", " as ", "", context, shape)
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}
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ast::ExprKind::Type(ref expr, ref ty) => {
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rewrite_pair(&**expr, &**ty, "", ": ", "", context, shape)
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}
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ast::ExprKind::Index(ref expr, ref index) => {
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rewrite_index(&**expr, &**index, context, shape)
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}
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ast::ExprKind::Repeat(ref expr, ref repeats) => {
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let (lbr, rbr) = if context.config.spaces_within_square_brackets() {
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("[ ", " ]")
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} else {
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("[", "]")
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};
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rewrite_pair(&**expr, &**repeats, lbr, "; ", rbr, context, shape)
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}
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ast::ExprKind::Range(ref lhs, ref rhs, limits) => {
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let delim = match limits {
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ast::RangeLimits::HalfOpen => "..",
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ast::RangeLimits::Closed => "...",
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};
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match (lhs.as_ref().map(|x| &**x), rhs.as_ref().map(|x| &**x)) {
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(Some(ref lhs), Some(ref rhs)) => {
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let sp_delim = if context.config.spaces_around_ranges() {
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format!(" {} ", delim)
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} else {
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delim.into()
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};
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rewrite_pair(&**lhs, &**rhs, "", &sp_delim, "", context, shape)
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}
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(None, Some(ref rhs)) => {
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let sp_delim = if context.config.spaces_around_ranges() {
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format!("{} ", delim)
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} else {
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delim.into()
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};
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rewrite_unary_prefix(context, &sp_delim, &**rhs, shape)
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}
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(Some(ref lhs), None) => {
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let sp_delim = if context.config.spaces_around_ranges() {
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format!(" {}", delim)
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} else {
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delim.into()
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};
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rewrite_unary_suffix(context, &sp_delim, &**lhs, shape)
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}
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(None, None) => wrap_str(delim.into(), context.config.max_width(), shape),
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}
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}
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// We do not format these expressions yet, but they should still
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// satisfy our width restrictions.
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ast::ExprKind::InPlace(..) |
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ast::ExprKind::InlineAsm(..) => {
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wrap_str(context.snippet(expr.span),
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context.config.max_width(),
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shape)
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}
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};
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match (attr_rw, expr_rw) {
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(Some(attr_str), Some(expr_str)) => {
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let space = if attr_str.is_empty() { "" } else { " " };
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recover_comment_removed(format!("{}{}{}", attr_str, space, expr_str),
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expr.span,
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context,
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shape)
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}
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_ => None,
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}
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}
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pub fn rewrite_pair<LHS, RHS>(lhs: &LHS,
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rhs: &RHS,
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prefix: &str,
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infix: &str,
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suffix: &str,
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context: &RewriteContext,
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shape: Shape)
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-> Option<String>
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where LHS: Rewrite,
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RHS: Rewrite
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{
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// Get "full width" rhs and see if it fits on the current line. This
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// usually works fairly well since it tends to place operands of
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// operations with high precendence close together.
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// Note that this is non-conservative, but its just to see if it's even
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// worth trying to put everything on one line.
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let rhs_shape = try_opt!(shape.sub_width(suffix.len()));
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let rhs_result = rhs.rewrite(context, rhs_shape);
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if let Some(rhs_result) = rhs_result {
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// This is needed in case of line break not caused by a
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// shortage of space, but by end-of-line comments, for example.
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if !rhs_result.contains('\n') {
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let lhs_shape = try_opt!(shape.sub_width(prefix.len() + infix.len()));
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let lhs_result = lhs.rewrite(context, lhs_shape);
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if let Some(lhs_result) = lhs_result {
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let mut result = format!("{}{}{}", prefix, lhs_result, infix);
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let remaining_width = shape
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.width
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.checked_sub(last_line_width(&result) + suffix.len())
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.unwrap_or(0);
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if rhs_result.len() <= remaining_width {
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result.push_str(&rhs_result);
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result.push_str(suffix);
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return Some(result);
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}
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// Try rewriting the rhs into the remaining space.
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let rhs_shape = shape.shrink_left(last_line_width(&result) + suffix.len());
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if let Some(rhs_shape) = rhs_shape {
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if let Some(rhs_result) = rhs.rewrite(context, rhs_shape) {
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// FIXME this should always hold.
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if rhs_result.len() <= remaining_width {
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result.push_str(&rhs_result);
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result.push_str(suffix);
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return Some(result);
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}
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}
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}
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}
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}
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}
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// We have to use multiple lines.
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// Re-evaluate the rhs because we have more space now:
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let infix = infix.trim_right();
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let rhs_shape = match context.config.control_style() {
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Style::Legacy => {
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try_opt!(shape.sub_width(suffix.len() + prefix.len())).visual_indent(prefix.len())
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}
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Style::Rfc => {
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shape
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.block_indent(context.config.tab_spaces())
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.with_max_width(context.config)
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}
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};
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let rhs_result = try_opt!(rhs.rewrite(context, rhs_shape));
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let lhs_shape = match context.config.control_style() {
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Style::Legacy => {
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let lhs_overhead = shape.used_width() + prefix.len() + infix.len();
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Shape {
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width: try_opt!(context.config.max_width().checked_sub(lhs_overhead)),
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..shape
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}
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}
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Style::Rfc => try_opt!(shape.sub_width(prefix.len() + infix.len())),
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};
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let lhs_result = try_opt!(lhs.rewrite(context, lhs_shape));
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Some(format!("{}{}{}\n{}{}{}",
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prefix,
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lhs_result,
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infix,
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rhs_shape.indent.to_string(context.config),
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rhs_result,
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suffix))
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}
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pub fn rewrite_array<'a, I>(expr_iter: I,
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span: Span,
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context: &RewriteContext,
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shape: Shape)
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-> Option<String>
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where I: Iterator<Item = &'a ast::Expr>
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{
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let bracket_size = if context.config.spaces_within_square_brackets() {
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2 // "[ "
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} else {
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1 // "["
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};
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let nested_shape = match context.config.array_layout() {
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IndentStyle::Block => shape.block().block_indent(context.config.tab_spaces()),
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IndentStyle::Visual => {
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try_opt!(shape
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.visual_indent(bracket_size)
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.sub_width(bracket_size * 2))
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}
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};
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let items = itemize_list(context.codemap,
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expr_iter,
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"]",
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|item| item.span.lo,
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|item| item.span.hi,
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|item| item.rewrite(context, nested_shape),
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span.lo,
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span.hi)
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.collect::<Vec<_>>();
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if items.is_empty() {
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if context.config.spaces_within_square_brackets() {
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return Some("[ ]".to_string());
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} else {
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return Some("[]".to_string());
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}
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}
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let has_long_item = try_opt!(items
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.iter()
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.map(|li| li.item.as_ref().map(|s| s.len() > 10))
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.fold(Some(false),
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|acc, x| acc.and_then(|y| x.map(|x| x || y))));
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let tactic = match context.config.array_layout() {
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IndentStyle::Block => {
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// FIXME wrong shape in one-line case
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match shape.width.checked_sub(2 * bracket_size) {
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Some(width) => {
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let tactic =
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ListTactic::LimitedHorizontalVertical(context.config.array_width());
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definitive_tactic(&items, tactic, width)
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}
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None => DefinitiveListTactic::Vertical,
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}
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}
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IndentStyle::Visual => {
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if has_long_item || items.iter().any(ListItem::is_multiline) {
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definitive_tactic(&items,
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ListTactic::LimitedHorizontalVertical(context
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.config
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.array_width()),
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nested_shape.width)
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} else {
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DefinitiveListTactic::Mixed
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}
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}
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};
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let fmt = ListFormatting {
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tactic: tactic,
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separator: ",",
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trailing_separator: SeparatorTactic::Never,
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shape: nested_shape,
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ends_with_newline: false,
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config: context.config,
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};
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let list_str = try_opt!(write_list(&items, &fmt));
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let result = if context.config.array_layout() == IndentStyle::Visual ||
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tactic != DefinitiveListTactic::Vertical {
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if context.config.spaces_within_square_brackets() && list_str.len() > 0 {
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format!("[ {} ]", list_str)
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} else {
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format!("[{}]", list_str)
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}
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} else {
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format!("[\n{}{},\n{}]",
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nested_shape.indent.to_string(context.config),
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list_str,
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shape.block().indent.to_string(context.config))
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};
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Some(result)
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}
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// This functions is pretty messy because of the rules around closures and blocks:
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// FIXME - the below is probably no longer true in full.
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// * if there is a return type, then there must be braces,
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// * given a closure with braces, whether that is parsed to give an inner block
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// or not depends on if there is a return type and if there are statements
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// in that block,
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// * if the first expression in the body ends with a block (i.e., is a
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// statement without needing a semi-colon), then adding or removing braces
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// can change whether it is treated as an expression or statement.
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fn rewrite_closure(capture: ast::CaptureBy,
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fn_decl: &ast::FnDecl,
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body: &ast::Expr,
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span: Span,
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context: &RewriteContext,
|
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shape: Shape)
|
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-> Option<String> {
|
|
let mover = if capture == ast::CaptureBy::Value {
|
|
"move "
|
|
} else {
|
|
""
|
|
};
|
|
// 4 = "|| {".len(), which is overconservative when the closure consists of
|
|
// a single expression.
|
|
let nested_shape = try_opt!(try_opt!(shape.shrink_left(mover.len())).sub_width(4));
|
|
|
|
// 1 = |
|
|
let argument_offset = nested_shape.indent + 1;
|
|
let arg_shape = try_opt!(nested_shape.shrink_left(1)).visual_indent(0);
|
|
let ret_str = try_opt!(fn_decl.output.rewrite(context, arg_shape));
|
|
|
|
let arg_items = itemize_list(context.codemap,
|
|
fn_decl.inputs.iter(),
|
|
"|",
|
|
|arg| span_lo_for_arg(arg),
|
|
|arg| span_hi_for_arg(arg),
|
|
|arg| arg.rewrite(context, arg_shape),
|
|
context.codemap.span_after(span, "|"),
|
|
body.span.lo);
|
|
let item_vec = arg_items.collect::<Vec<_>>();
|
|
// 1 = space between arguments and return type.
|
|
let horizontal_budget = nested_shape
|
|
.width
|
|
.checked_sub(ret_str.len() + 1)
|
|
.unwrap_or(0);
|
|
let tactic = definitive_tactic(&item_vec, ListTactic::HorizontalVertical, horizontal_budget);
|
|
let arg_shape = match tactic {
|
|
DefinitiveListTactic::Horizontal => try_opt!(arg_shape.sub_width(ret_str.len() + 1)),
|
|
_ => arg_shape,
|
|
};
|
|
|
|
let fmt = ListFormatting {
|
|
tactic: tactic,
|
|
separator: ",",
|
|
trailing_separator: SeparatorTactic::Never,
|
|
shape: arg_shape,
|
|
ends_with_newline: false,
|
|
config: context.config,
|
|
};
|
|
let list_str = try_opt!(write_list(&item_vec, &fmt));
|
|
let mut prefix = format!("{}|{}|", mover, list_str);
|
|
|
|
if !ret_str.is_empty() {
|
|
if prefix.contains('\n') {
|
|
prefix.push('\n');
|
|
prefix.push_str(&argument_offset.to_string(context.config));
|
|
} else {
|
|
prefix.push(' ');
|
|
}
|
|
prefix.push_str(&ret_str);
|
|
}
|
|
|
|
// 1 = space between `|...|` and body.
|
|
let extra_offset = extra_offset(&prefix, shape) + 1;
|
|
let body_shape = try_opt!(shape.sub_width(extra_offset)).add_offset(extra_offset);
|
|
|
|
if let ast::ExprKind::Block(ref block) = body.node {
|
|
// The body of the closure is an empty block.
|
|
if block.stmts.is_empty() && !block_contains_comment(block, context.codemap) {
|
|
return Some(format!("{} {{}}", prefix));
|
|
}
|
|
|
|
// Figure out if the block is necessary.
|
|
let needs_block = block.rules != ast::BlockCheckMode::Default ||
|
|
block.stmts.len() > 1 || context.inside_macro ||
|
|
block_contains_comment(block, context.codemap) ||
|
|
prefix.contains('\n');
|
|
|
|
if ret_str.is_empty() && !needs_block {
|
|
// lock.stmts.len() == 1
|
|
if let Some(ref expr) = stmt_expr(&block.stmts[0]) {
|
|
if let Some(rw) = rewrite_closure_expr(expr, &prefix, context, body_shape) {
|
|
return Some(rw);
|
|
}
|
|
}
|
|
}
|
|
|
|
if !needs_block {
|
|
// We need braces, but we might still prefer a one-liner.
|
|
let stmt = &block.stmts[0];
|
|
// 4 = braces and spaces.
|
|
if let Some(body_shape) = body_shape.sub_width(4) {
|
|
// Checks if rewrite succeeded and fits on a single line.
|
|
if let Some(rewrite) = and_one_line(stmt.rewrite(context, body_shape)) {
|
|
return Some(format!("{} {{ {} }}", prefix, rewrite));
|
|
}
|
|
}
|
|
}
|
|
|
|
// Either we require a block, or tried without and failed.
|
|
return rewrite_closure_block(&block, prefix, context, body_shape);
|
|
}
|
|
|
|
if let Some(rw) = rewrite_closure_expr(body, &prefix, context, body_shape) {
|
|
return Some(rw);
|
|
}
|
|
|
|
// The closure originally had a non-block expression, but we can't fit on
|
|
// one line, so we'll insert a block.
|
|
let block = ast::Block {
|
|
stmts: vec![ast::Stmt {
|
|
id: ast::NodeId::new(0),
|
|
node: ast::StmtKind::Expr(ptr::P(body.clone())),
|
|
span: body.span,
|
|
}],
|
|
id: ast::NodeId::new(0),
|
|
rules: ast::BlockCheckMode::Default,
|
|
span: body.span,
|
|
};
|
|
return rewrite_closure_block(&block, prefix, context, body_shape);
|
|
|
|
fn rewrite_closure_expr(expr: &ast::Expr,
|
|
prefix: &str,
|
|
context: &RewriteContext,
|
|
shape: Shape)
|
|
-> Option<String> {
|
|
let mut rewrite = expr.rewrite(context, shape);
|
|
if classify::expr_requires_semi_to_be_stmt(left_most_sub_expr(expr)) {
|
|
rewrite = and_one_line(rewrite);
|
|
}
|
|
rewrite.map(|rw| format!("{} {}", prefix, rw))
|
|
}
|
|
|
|
fn rewrite_closure_block(block: &ast::Block,
|
|
prefix: String,
|
|
context: &RewriteContext,
|
|
shape: Shape)
|
|
-> Option<String> {
|
|
// Start with visual indent, then fall back to block indent if the
|
|
// closure is large.
|
|
let block_threshold = context.config.closure_block_indent_threshold();
|
|
if block_threshold >= 0 {
|
|
if let Some(block_str) = block.rewrite(&context, shape) {
|
|
if block_str.matches('\n').count() <= block_threshold as usize &&
|
|
!need_block_indent(&block_str, shape) {
|
|
if let Some(block_str) = block_str.rewrite(context, shape) {
|
|
return Some(format!("{} {}", prefix, block_str));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// The body of the closure is big enough to be block indented, that
|
|
// means we must re-format.
|
|
let block_shape = shape.block().with_max_width(context.config);
|
|
let block_str = try_opt!(block.rewrite(&context, block_shape));
|
|
Some(format!("{} {}",
|
|
prefix,
|
|
try_opt!(block_str.rewrite(context, block_shape))))
|
|
}
|
|
}
|
|
|
|
fn and_one_line(x: Option<String>) -> Option<String> {
|
|
x.and_then(|x| if x.contains('\n') { None } else { Some(x) })
|
|
}
|
|
|
|
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()
|
|
})
|
|
}
|
|
|
|
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 self.stmts.is_empty() && !block_contains_comment(self, 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(self.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 self.stmts.is_empty() && !comment_str.contains('\n') &&
|
|
!comment_str.starts_with("//") &&
|
|
comment_str.len() + 4 <= shape.width {
|
|
return Some(format!("{{ {} }}", comment_str));
|
|
}
|
|
}
|
|
|
|
let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
|
|
visitor.block_indent = shape.indent;
|
|
visitor.is_if_else_block = context.is_if_else_block;
|
|
|
|
let prefix = match self.rules {
|
|
ast::BlockCheckMode::Unsafe(..) => {
|
|
let snippet = context.snippet(self.span);
|
|
let open_pos = try_opt!(snippet.find_uncommented("{"));
|
|
visitor.last_pos = self.span.lo + BytePos(open_pos as u32);
|
|
|
|
// Extract comment between unsafe and block start.
|
|
let trimmed = &snippet[6..open_pos].trim();
|
|
|
|
let prefix = if !trimmed.is_empty() {
|
|
// 9 = "unsafe {".len(), 7 = "unsafe ".len()
|
|
let budget = try_opt!(shape.width.checked_sub(9));
|
|
format!("unsafe {} ",
|
|
try_opt!(rewrite_comment(trimmed,
|
|
true,
|
|
Shape::legacy(budget, shape.indent + 7),
|
|
context.config)))
|
|
} else {
|
|
"unsafe ".to_owned()
|
|
};
|
|
|
|
if is_simple_block(self, context.codemap) && prefix.len() < shape.width {
|
|
let expr_str =
|
|
self.stmts[0].rewrite(context,
|
|
Shape::legacy(shape.width - prefix.len(),
|
|
shape.indent));
|
|
let expr_str = try_opt!(expr_str);
|
|
let result = format!("{}{{ {} }}", prefix, expr_str);
|
|
if result.len() <= shape.width && !result.contains('\n') {
|
|
return Some(result);
|
|
}
|
|
}
|
|
|
|
prefix
|
|
}
|
|
ast::BlockCheckMode::Default => {
|
|
visitor.last_pos = self.span.lo;
|
|
|
|
String::new()
|
|
}
|
|
};
|
|
|
|
visitor.visit_block(self);
|
|
if visitor.failed && shape.indent.alignment != 0 {
|
|
self.rewrite(context,
|
|
Shape::indented(shape.indent.block_only(), context.config))
|
|
} else {
|
|
Some(format!("{}{}", prefix, visitor.buffer))
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Rewrite for ast::Stmt {
|
|
fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
|
|
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(self) { ";" } else { "" };
|
|
|
|
format_expr(ex,
|
|
match self.node {
|
|
ast::StmtKind::Expr(_) => ExprType::SubExpression,
|
|
ast::StmtKind::Semi(_) => ExprType::Statement,
|
|
_ => unreachable!(),
|
|
},
|
|
context,
|
|
try_opt!(shape.sub_width(suffix.len())))
|
|
.map(|s| s + suffix)
|
|
}
|
|
ast::StmtKind::Mac(..) |
|
|
ast::StmtKind::Item(..) => None,
|
|
};
|
|
result.and_then(|res| recover_comment_removed(res, self.span, context, shape))
|
|
}
|
|
}
|
|
|
|
// 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::SpannedIdent>,
|
|
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,
|
|
}
|
|
|
|
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: block,
|
|
else_block: else_block,
|
|
label: None,
|
|
pat: pat,
|
|
keyword: "if",
|
|
matcher: match pat {
|
|
Some(..) => "let",
|
|
None => "",
|
|
},
|
|
connector: " =",
|
|
allow_single_line: allow_single_line,
|
|
nested_if: nested_if,
|
|
span: span,
|
|
}
|
|
}
|
|
|
|
fn new_loop(block: &'a ast::Block,
|
|
label: Option<ast::SpannedIdent>,
|
|
span: Span)
|
|
-> ControlFlow<'a> {
|
|
ControlFlow {
|
|
cond: None,
|
|
block: block,
|
|
else_block: None,
|
|
label: label,
|
|
pat: None,
|
|
keyword: "loop",
|
|
matcher: "",
|
|
connector: "",
|
|
allow_single_line: false,
|
|
nested_if: false,
|
|
span: span,
|
|
}
|
|
}
|
|
|
|
fn new_while(pat: Option<&'a ast::Pat>,
|
|
cond: &'a ast::Expr,
|
|
block: &'a ast::Block,
|
|
label: Option<ast::SpannedIdent>,
|
|
span: Span)
|
|
-> ControlFlow<'a> {
|
|
ControlFlow {
|
|
cond: Some(cond),
|
|
block: block,
|
|
else_block: None,
|
|
label: label,
|
|
pat: pat,
|
|
keyword: "while",
|
|
matcher: match pat {
|
|
Some(..) => "let",
|
|
None => "",
|
|
},
|
|
connector: " =",
|
|
allow_single_line: false,
|
|
nested_if: false,
|
|
span: span,
|
|
}
|
|
}
|
|
|
|
fn new_for(pat: &'a ast::Pat,
|
|
cond: &'a ast::Expr,
|
|
block: &'a ast::Block,
|
|
label: Option<ast::SpannedIdent>,
|
|
span: Span)
|
|
-> ControlFlow<'a> {
|
|
ControlFlow {
|
|
cond: Some(cond),
|
|
block: block,
|
|
else_block: None,
|
|
label: label,
|
|
pat: Some(pat),
|
|
keyword: "for",
|
|
matcher: "",
|
|
connector: " in",
|
|
allow_single_line: false,
|
|
nested_if: false,
|
|
span: span,
|
|
}
|
|
}
|
|
|
|
fn rewrite_single_line(&self,
|
|
pat_expr_str: &str,
|
|
context: &RewriteContext,
|
|
width: usize)
|
|
-> Option<String> {
|
|
assert!(self.allow_single_line);
|
|
let else_block = try_opt!(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 = try_opt!(width.checked_sub(pat_expr_str.len() + fixed_cost));
|
|
let expr = &self.block.stmts[0];
|
|
let if_str = try_opt!(expr.rewrite(context, Shape::legacy(new_width, Indent::empty())));
|
|
|
|
let new_width = try_opt!(new_width.checked_sub(if_str.len()));
|
|
let else_expr = &else_node.stmts[0];
|
|
let else_str =
|
|
try_opt!(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> Rewrite for ControlFlow<'a> {
|
|
fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
|
|
debug!("ControlFlow::rewrite {:?} {:?}", self, shape);
|
|
let constr_shape = if self.nested_if {
|
|
// We are part of an if-elseif-else chain. Our constraints are tightened.
|
|
// 7 = "} else " .len()
|
|
try_opt!(shape.shrink_left(7))
|
|
} else {
|
|
shape
|
|
};
|
|
|
|
let label_string = rewrite_label(self.label);
|
|
// 1 = space after keyword.
|
|
let add_offset = self.keyword.len() + label_string.len() + 1;
|
|
|
|
let pat_expr_string = match self.cond {
|
|
Some(cond) => {
|
|
let mut cond_shape = match context.config.control_style() {
|
|
Style::Legacy => try_opt!(constr_shape.shrink_left(add_offset)),
|
|
Style::Rfc => try_opt!(constr_shape.sub_width(add_offset)),
|
|
};
|
|
if context.config.control_brace_style() != ControlBraceStyle::AlwaysNextLine {
|
|
// 2 = " {".len()
|
|
cond_shape = try_opt!(cond_shape.sub_width(2));
|
|
}
|
|
|
|
try_opt!(rewrite_pat_expr(context,
|
|
self.pat,
|
|
cond,
|
|
self.matcher,
|
|
self.connector,
|
|
self.keyword,
|
|
cond_shape))
|
|
}
|
|
None => String::new(),
|
|
};
|
|
|
|
let force_newline_brace = context.config.control_style() == Style::Rfc &&
|
|
pat_expr_string.contains('\n');
|
|
|
|
// Try to format if-else on single line.
|
|
if self.allow_single_line && context.config.single_line_if_else_max_width() > 0 {
|
|
let trial = self.rewrite_single_line(&pat_expr_string, context, shape.width);
|
|
|
|
if trial.is_some() &&
|
|
trial.as_ref().unwrap().len() <= context.config.single_line_if_else_max_width() {
|
|
return trial;
|
|
}
|
|
}
|
|
|
|
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
|
|
};
|
|
|
|
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 = try_opt!(self.block.rewrite(&block_context, block_shape));
|
|
|
|
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
|
|
let between_kwd_cond = mk_sp(
|
|
context.codemap.span_after(self.span, 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 alt_block_sep = String::from("\n") +
|
|
&shape.indent.block_only().to_string(context.config);
|
|
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.as_str()
|
|
} else {
|
|
" "
|
|
};
|
|
|
|
let mut result = 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),
|
|
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
|
|
};
|
|
else_block.rewrite(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,
|
|
_ => " ",
|
|
};
|
|
try_opt!(write!(&mut result,
|
|
"{}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))
|
|
.ok());
|
|
result.push_str(&try_opt!(rewrite));
|
|
}
|
|
|
|
Some(result)
|
|
}
|
|
}
|
|
|
|
fn rewrite_label(label: Option<ast::SpannedIdent>) -> String {
|
|
match label {
|
|
Some(ident) => format!("{}: ", ident.node),
|
|
None => "".to_owned(),
|
|
}
|
|
}
|
|
|
|
fn extract_comment(span: Span, context: &RewriteContext, shape: Shape) -> Option<String> {
|
|
let comment_str = context.snippet(span);
|
|
if contains_comment(&comment_str) {
|
|
let comment = try_opt!(rewrite_comment(comment_str.trim(), false, shape, context.config));
|
|
Some(format!("\n{indent}{}\n{indent}",
|
|
comment,
|
|
indent = shape.indent.to_string(context.config)))
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
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,
|
|
}
|
|
}
|
|
|
|
fn is_unsafe_block(block: &ast::Block) -> bool {
|
|
if let ast::BlockCheckMode::Unsafe(..) = block.rules {
|
|
true
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
// inter-match-arm-comment-rules:
|
|
// - all comments following a match arm before the start of the next arm
|
|
// are about the second arm
|
|
fn rewrite_match_arm_comment(context: &RewriteContext,
|
|
missed_str: &str,
|
|
shape: Shape,
|
|
arm_indent_str: &str)
|
|
-> Option<String> {
|
|
// The leading "," is not part of the arm-comment
|
|
let missed_str = match missed_str.find_uncommented(",") {
|
|
Some(n) => &missed_str[n + 1..],
|
|
None => &missed_str[..],
|
|
};
|
|
|
|
let mut result = String::new();
|
|
// any text not preceeded by a newline is pushed unmodified to the block
|
|
let first_brk = missed_str.find(|c: char| c == '\n').unwrap_or(0);
|
|
result.push_str(&missed_str[..first_brk]);
|
|
let missed_str = &missed_str[first_brk..]; // If missed_str had one newline, it starts with it
|
|
|
|
let first = missed_str
|
|
.find(|c: char| !c.is_whitespace())
|
|
.unwrap_or(missed_str.len());
|
|
if missed_str[..first].chars().filter(|c| c == &'\n').count() >= 2 {
|
|
// Excessive vertical whitespace before comment should be preserved
|
|
// FIXME handle vertical whitespace better
|
|
result.push('\n');
|
|
}
|
|
let missed_str = missed_str[first..].trim();
|
|
if !missed_str.is_empty() {
|
|
let comment = try_opt!(rewrite_comment(&missed_str, false, shape, context.config));
|
|
result.push('\n');
|
|
result.push_str(arm_indent_str);
|
|
result.push_str(&comment);
|
|
}
|
|
|
|
Some(result)
|
|
}
|
|
|
|
fn rewrite_match(context: &RewriteContext,
|
|
cond: &ast::Expr,
|
|
arms: &[ast::Arm],
|
|
shape: Shape,
|
|
span: Span)
|
|
-> Option<String> {
|
|
if arms.is_empty() {
|
|
return None;
|
|
}
|
|
|
|
// `match `cond` {`
|
|
let cond_shape = try_opt!(shape.shrink_left(6));
|
|
let cond_shape = try_opt!(cond_shape.sub_width(2));
|
|
let cond_str = try_opt!(cond.rewrite(context, cond_shape));
|
|
let alt_block_sep = String::from("\n") + &shape.indent.block_only().to_string(context.config);
|
|
let block_sep = match context.config.control_brace_style() {
|
|
ControlBraceStyle::AlwaysSameLine => " ",
|
|
_ => alt_block_sep.as_str(),
|
|
};
|
|
let mut result = format!("match {}{}{{", cond_str, block_sep);
|
|
|
|
let arm_shape = if context.config.indent_match_arms() {
|
|
shape.block_indent(context.config.tab_spaces())
|
|
} else {
|
|
shape.block_indent(0)
|
|
};
|
|
|
|
let arm_indent_str = arm_shape.indent.to_string(context.config);
|
|
|
|
let open_brace_pos = context
|
|
.codemap
|
|
.span_after(mk_sp(cond.span.hi, arm_start_pos(&arms[0])), "{");
|
|
|
|
for (i, arm) in arms.iter().enumerate() {
|
|
// Make sure we get the stuff between arms.
|
|
let missed_str = if i == 0 {
|
|
context.snippet(mk_sp(open_brace_pos, arm_start_pos(arm)))
|
|
} else {
|
|
context.snippet(mk_sp(arm_end_pos(&arms[i - 1]), arm_start_pos(arm)))
|
|
};
|
|
let comment =
|
|
try_opt!(rewrite_match_arm_comment(context, &missed_str, arm_shape, &arm_indent_str));
|
|
result.push_str(&comment);
|
|
result.push('\n');
|
|
result.push_str(&arm_indent_str);
|
|
|
|
let arm_str = arm.rewrite(&context, arm_shape.with_max_width(context.config));
|
|
if let Some(ref arm_str) = arm_str {
|
|
result.push_str(arm_str);
|
|
} else {
|
|
// We couldn't format the arm, just reproduce the source.
|
|
let snippet = context.snippet(mk_sp(arm_start_pos(arm), arm_end_pos(arm)));
|
|
result.push_str(&snippet);
|
|
result.push_str(arm_comma(context.config, &arm.body));
|
|
}
|
|
}
|
|
// BytePos(1) = closing match brace.
|
|
let last_span = mk_sp(arm_end_pos(&arms[arms.len() - 1]), span.hi - BytePos(1));
|
|
let last_comment = context.snippet(last_span);
|
|
let comment =
|
|
try_opt!(rewrite_match_arm_comment(context, &last_comment, arm_shape, &arm_indent_str));
|
|
result.push_str(&comment);
|
|
result.push('\n');
|
|
result.push_str(&shape.indent.to_string(context.config));
|
|
result.push('}');
|
|
Some(result)
|
|
}
|
|
|
|
fn arm_start_pos(arm: &ast::Arm) -> BytePos {
|
|
let &ast::Arm {
|
|
ref attrs,
|
|
ref pats,
|
|
..
|
|
} = arm;
|
|
if !attrs.is_empty() {
|
|
return attrs[0].span.lo;
|
|
}
|
|
|
|
pats[0].span.lo
|
|
}
|
|
|
|
fn arm_end_pos(arm: &ast::Arm) -> BytePos {
|
|
arm.body.span.hi
|
|
}
|
|
|
|
fn arm_comma(config: &Config, body: &ast::Expr) -> &'static str {
|
|
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 {
|
|
","
|
|
}
|
|
}
|
|
|
|
// Match arms.
|
|
impl Rewrite for ast::Arm {
|
|
fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
|
|
debug!("Arm::rewrite {:?} {:?}", self, shape);
|
|
let &ast::Arm {
|
|
ref attrs,
|
|
ref pats,
|
|
ref guard,
|
|
ref body,
|
|
} = self;
|
|
|
|
// FIXME this is all a bit grotty, would be nice to abstract out the
|
|
// treatment of attributes.
|
|
let attr_str = if !attrs.is_empty() {
|
|
// We only use this visitor for the attributes, should we use it for
|
|
// more?
|
|
let mut attr_visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
|
|
attr_visitor.block_indent = shape.indent.block_only();
|
|
attr_visitor.last_pos = attrs[0].span.lo;
|
|
if attr_visitor.visit_attrs(attrs) {
|
|
// Attributes included a skip instruction.
|
|
return None;
|
|
}
|
|
attr_visitor.format_missing(pats[0].span.lo);
|
|
attr_visitor.buffer.to_string()
|
|
} else {
|
|
String::new()
|
|
};
|
|
|
|
// Patterns
|
|
// 5 = ` => {`
|
|
let pat_shape = try_opt!(shape.sub_width(5));
|
|
|
|
let pat_strs = try_opt!(pats.iter()
|
|
.map(|p| p.rewrite(context, pat_shape))
|
|
.collect::<Option<Vec<_>>>());
|
|
|
|
let all_simple = pat_strs.iter().all(|p| pat_is_simple(p));
|
|
let items: Vec<_> = pat_strs.into_iter().map(ListItem::from_str).collect();
|
|
let fmt = ListFormatting {
|
|
tactic: if all_simple {
|
|
DefinitiveListTactic::Mixed
|
|
} else {
|
|
DefinitiveListTactic::Vertical
|
|
},
|
|
separator: " |",
|
|
trailing_separator: SeparatorTactic::Never,
|
|
shape: pat_shape,
|
|
ends_with_newline: false,
|
|
config: context.config,
|
|
};
|
|
let pats_str = try_opt!(write_list(items, &fmt));
|
|
|
|
let guard_shape = if pats_str.contains('\n') {
|
|
shape.with_max_width(context.config)
|
|
} else {
|
|
shape
|
|
};
|
|
|
|
let guard_str = try_opt!(rewrite_guard(context,
|
|
guard,
|
|
guard_shape,
|
|
trimmed_last_line_width(&pats_str)));
|
|
|
|
let pats_str = format!("{}{}", pats_str, guard_str);
|
|
|
|
let (mut extend, body) = match body.node {
|
|
ast::ExprKind::Block(ref block) if !is_unsafe_block(block) &&
|
|
is_simple_block(block, context.codemap) &&
|
|
context.config.wrap_match_arms() => {
|
|
if let ast::StmtKind::Expr(ref expr) = block.stmts[0].node {
|
|
(false, &**expr)
|
|
} else {
|
|
(false, &**body)
|
|
}
|
|
}
|
|
ast::ExprKind::Call(_, ref args) => (args.len() == 1, &**body),
|
|
ast::ExprKind::Closure(..) |
|
|
ast::ExprKind::Struct(..) |
|
|
ast::ExprKind::Tup(..) => (true, &**body),
|
|
_ => (false, &**body),
|
|
};
|
|
extend &= context.config.fn_call_style() == IndentStyle::Block;
|
|
|
|
let comma = arm_comma(&context.config, body);
|
|
let alt_block_sep = String::from("\n") +
|
|
&shape.indent.block_only().to_string(context.config);
|
|
|
|
let pat_width = extra_offset(&pats_str, shape);
|
|
// Let's try and get the arm body on the same line as the condition.
|
|
// 4 = ` => `.len()
|
|
if shape.width > pat_width + comma.len() + 4 {
|
|
let arm_shape = shape
|
|
.offset_left(pat_width + 4)
|
|
.unwrap()
|
|
.sub_width(comma.len())
|
|
.unwrap();
|
|
let rewrite = nop_block_collapse(body.rewrite(context, arm_shape), arm_shape.width);
|
|
let is_block = if let ast::ExprKind::Block(..) = body.node {
|
|
true
|
|
} else {
|
|
false
|
|
};
|
|
|
|
match rewrite {
|
|
Some(ref body_str) if (!body_str.contains('\n') &&
|
|
body_str.len() <= arm_shape.width) ||
|
|
!context.config.wrap_match_arms() ||
|
|
(extend && first_line_width(body_str) <= arm_shape.width) ||
|
|
is_block => {
|
|
let block_sep = match context.config.control_brace_style() {
|
|
ControlBraceStyle::AlwaysNextLine if is_block => alt_block_sep.as_str(),
|
|
_ => " ",
|
|
};
|
|
|
|
return Some(format!("{}{} =>{}{}{}",
|
|
attr_str.trim_left(),
|
|
pats_str,
|
|
block_sep,
|
|
body_str,
|
|
comma));
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
|
|
// FIXME: we're doing a second rewrite of the expr; This may not be
|
|
// necessary.
|
|
let body_shape = try_opt!(shape.sub_width(context.config.tab_spaces()))
|
|
.block_indent(context.config.tab_spaces());
|
|
let next_line_body = try_opt!(nop_block_collapse(body.rewrite(context, body_shape),
|
|
body_shape.width));
|
|
let indent_str = shape
|
|
.indent
|
|
.block_indent(context.config)
|
|
.to_string(context.config);
|
|
let (body_prefix, body_suffix) = if context.config.wrap_match_arms() {
|
|
if context.config.match_block_trailing_comma() {
|
|
("{", "},")
|
|
} else {
|
|
("{", "}")
|
|
}
|
|
} else {
|
|
("", ",")
|
|
};
|
|
|
|
|
|
let block_sep = match context.config.control_brace_style() {
|
|
ControlBraceStyle::AlwaysNextLine => alt_block_sep + body_prefix + "\n",
|
|
_ if body_prefix.is_empty() => "\n".to_owned(),
|
|
_ => " ".to_owned() + body_prefix + "\n",
|
|
};
|
|
|
|
if context.config.wrap_match_arms() {
|
|
Some(format!("{}{} =>{}{}{}\n{}{}",
|
|
attr_str.trim_left(),
|
|
pats_str,
|
|
block_sep,
|
|
indent_str,
|
|
next_line_body,
|
|
shape.indent.to_string(context.config),
|
|
body_suffix))
|
|
} else {
|
|
Some(format!("{}{} =>{}{}{}{}",
|
|
attr_str.trim_left(),
|
|
pats_str,
|
|
block_sep,
|
|
indent_str,
|
|
next_line_body,
|
|
body_suffix))
|
|
}
|
|
}
|
|
}
|
|
|
|
// A pattern is simple if it is very short or it is short-ish and just a path.
|
|
// E.g. `Foo::Bar` is simple, but `Foo(..)` is not.
|
|
fn pat_is_simple(pat_str: &str) -> bool {
|
|
pat_str.len() <= 16 ||
|
|
(pat_str.len() <= 24 && pat_str.chars().all(|c| c.is_alphabetic() || c == ':'))
|
|
}
|
|
|
|
// 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 overhead = pattern_width + 4 + 5;
|
|
if overhead < shape.width {
|
|
let cond_shape = shape
|
|
.shrink_left(pattern_width + 4)
|
|
.unwrap()
|
|
.sub_width(5)
|
|
.unwrap();
|
|
let cond_str = guard.rewrite(context, cond_shape);
|
|
if let Some(cond_str) = cond_str {
|
|
return Some(format!(" if {}", cond_str));
|
|
}
|
|
}
|
|
|
|
// Not enough space to put the guard after the pattern, try a newline.
|
|
let overhead = shape.indent.block_indent(context.config).width() + 4 + 5;
|
|
if overhead < shape.width {
|
|
let cond_str = guard.rewrite(context,
|
|
Shape::legacy(shape.width - overhead,
|
|
// 3 == `if `
|
|
shape.indent.block_indent(context.config) +
|
|
3));
|
|
if let Some(cond_str) = cond_str {
|
|
return Some(format!("\n{}if {}",
|
|
shape
|
|
.indent
|
|
.block_indent(context.config)
|
|
.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)
|
|
-> Option<String> {
|
|
debug!("rewrite_pat_expr {:?} {:?} {:?}", shape, pat, expr);
|
|
let mut pat_string = String::new();
|
|
let mut result = match pat {
|
|
Some(pat) => {
|
|
let matcher = if matcher.is_empty() {
|
|
matcher.to_owned()
|
|
} else {
|
|
format!("{} ", matcher)
|
|
};
|
|
let pat_shape = try_opt!(try_opt!(shape.shrink_left(matcher.len()))
|
|
.sub_width(connector.len()));
|
|
pat_string = try_opt!(pat.rewrite(context, pat_shape));
|
|
format!("{}{}{}", matcher, pat_string, connector)
|
|
}
|
|
None => String::new(),
|
|
};
|
|
|
|
// Consider only the last line of the pat string.
|
|
let extra_offset = extra_offset(&result, shape);
|
|
|
|
// The expression may (partially) fit on the current line.
|
|
if shape.width > extra_offset + 1 {
|
|
let spacer = if pat.is_some() { " " } else { "" };
|
|
|
|
let expr_shape = try_opt!(shape.offset_left(extra_offset + spacer.len()));
|
|
let expr_rewrite = expr.rewrite(context, expr_shape);
|
|
|
|
if let Some(expr_string) = expr_rewrite {
|
|
if pat.is_none() || pat_is_simple(&pat_string) || !expr_string.contains('\n') {
|
|
result.push_str(spacer);
|
|
result.push_str(&expr_string);
|
|
return Some(result);
|
|
}
|
|
}
|
|
}
|
|
|
|
if pat.is_none() && keyword == "if" {
|
|
return None;
|
|
}
|
|
|
|
let nested_indent = shape.indent.block_only().block_indent(context.config);
|
|
|
|
// The expression won't fit on the current line, jump to next.
|
|
result.push('\n');
|
|
result.push_str(&nested_indent.to_string(context.config));
|
|
|
|
let expr_rewrite = expr.rewrite(&context, Shape::indented(nested_indent, context.config));
|
|
result.push_str(&try_opt!(expr_rewrite));
|
|
|
|
Some(result)
|
|
}
|
|
|
|
fn rewrite_string_lit(context: &RewriteContext, span: Span, shape: Shape) -> Option<String> {
|
|
let string_lit = context.snippet(span);
|
|
|
|
if !context.config.format_strings() && !context.config.force_format_strings() {
|
|
return Some(string_lit);
|
|
}
|
|
|
|
if !context.config.force_format_strings() &&
|
|
!string_requires_rewrite(context, span, &string_lit, shape) {
|
|
return Some(string_lit);
|
|
}
|
|
|
|
let fmt = StringFormat {
|
|
opener: "\"",
|
|
closer: "\"",
|
|
line_start: " ",
|
|
line_end: "\\",
|
|
shape: shape,
|
|
trim_end: false,
|
|
config: context.config,
|
|
};
|
|
|
|
// Remove the quote characters.
|
|
let str_lit = &string_lit[1..string_lit.len() - 1];
|
|
|
|
rewrite_string(str_lit, &fmt)
|
|
}
|
|
|
|
fn string_requires_rewrite(context: &RewriteContext,
|
|
span: Span,
|
|
string: &str,
|
|
shape: Shape)
|
|
-> bool {
|
|
if context.codemap.lookup_char_pos(span.lo).col.0 != shape.indent.width() {
|
|
return true;
|
|
}
|
|
|
|
for (i, line) in string.lines().enumerate() {
|
|
if i == 0 {
|
|
if line.len() > shape.width {
|
|
return true;
|
|
}
|
|
} else {
|
|
if line.len() > shape.width + shape.indent.width() {
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
false
|
|
}
|
|
|
|
pub fn rewrite_call_with_binary_search<R>(context: &RewriteContext,
|
|
callee: &R,
|
|
args: &[ptr::P<ast::Expr>],
|
|
span: Span,
|
|
shape: Shape)
|
|
-> Option<String>
|
|
where R: Rewrite
|
|
{
|
|
let closure = |callee_max_width| {
|
|
// FIXME using byte lens instead of char lens (and probably all over the
|
|
// place too)
|
|
let callee_shape = Shape {
|
|
width: callee_max_width,
|
|
..shape
|
|
};
|
|
let callee_str = callee
|
|
.rewrite(context, callee_shape)
|
|
.ok_or(Ordering::Greater)?;
|
|
|
|
rewrite_call_inner(context, &callee_str, args, span, shape, false)
|
|
};
|
|
|
|
binary_search(1, shape.width, closure)
|
|
}
|
|
|
|
pub fn rewrite_call(context: &RewriteContext,
|
|
callee: &str,
|
|
args: &[ptr::P<ast::Expr>],
|
|
span: Span,
|
|
shape: Shape)
|
|
-> Option<String> {
|
|
rewrite_call_inner(context, &callee, args, span, shape, false).ok()
|
|
}
|
|
|
|
fn rewrite_call_inner(context: &RewriteContext,
|
|
callee_str: &str,
|
|
args: &[ptr::P<ast::Expr>],
|
|
span: Span,
|
|
shape: Shape,
|
|
force_trailing_comma: bool)
|
|
-> Result<String, Ordering> {
|
|
// 2 = `( `, 1 = `(`
|
|
let paren_overhead = if context.config.spaces_within_parens() {
|
|
2
|
|
} else {
|
|
1
|
|
};
|
|
let used_width = extra_offset(&callee_str, shape);
|
|
let one_line_width = shape
|
|
.width
|
|
.checked_sub(used_width + 2 * paren_overhead)
|
|
.ok_or(Ordering::Greater)?;
|
|
|
|
let nested_shape = shape_from_fn_call_style(context,
|
|
shape,
|
|
used_width + 2 * paren_overhead,
|
|
used_width + paren_overhead)
|
|
.ok_or(Ordering::Greater)?;
|
|
|
|
let span_lo = context.codemap.span_after(span, "(");
|
|
let new_span = mk_sp(span_lo, span.hi);
|
|
|
|
let (extendable, list_str) = rewrite_call_args(context,
|
|
args,
|
|
new_span,
|
|
nested_shape,
|
|
one_line_width,
|
|
force_trailing_comma)
|
|
.ok_or(Ordering::Less)?;
|
|
|
|
if !use_block_indent(context) && 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,
|
|
force_trailing_comma);
|
|
}
|
|
|
|
Ok(format!("{}{}",
|
|
callee_str,
|
|
wrap_args_with_parens(context, &list_str, extendable, 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(context: &RewriteContext,
|
|
args: &[ptr::P<ast::Expr>],
|
|
span: Span,
|
|
shape: Shape,
|
|
one_line_width: usize,
|
|
force_trailing_comma: bool)
|
|
-> Option<(bool, String)> {
|
|
let mut item_context = context.clone();
|
|
item_context.inside_macro = false;
|
|
let items = itemize_list(context.codemap,
|
|
args.iter(),
|
|
")",
|
|
|item| item.span.lo,
|
|
|item| item.span.hi,
|
|
|item| item.rewrite(&item_context, shape),
|
|
span.lo,
|
|
span.hi);
|
|
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 overflow_last = can_be_overflowed(&item_context, args);
|
|
|
|
let mut orig_last = None;
|
|
let mut placeholder = None;
|
|
|
|
// Replace the last item with its first line to see if it fits with
|
|
// first arguments.
|
|
if overflow_last {
|
|
let arg_shape = if use_block_indent(context) && is_extendable(args) {
|
|
Shape {
|
|
width: context.config.fn_call_width(),
|
|
indent: shape.block().indent.block_unindent(context.config),
|
|
offset: 0,
|
|
}
|
|
} else {
|
|
shape.block()
|
|
};
|
|
let rewrite = args.last().unwrap().rewrite(&item_context, arg_shape);
|
|
swap(&mut item_vec[args.len() - 1].item, &mut orig_last);
|
|
|
|
if let Some(rewrite) = rewrite {
|
|
let rewrite_first_line = Some(rewrite[..first_line_width(&rewrite)].to_owned());
|
|
placeholder = Some(rewrite);
|
|
|
|
item_vec[args.len() - 1].item = rewrite_first_line;
|
|
}
|
|
}
|
|
|
|
let one_line_shape = Shape {
|
|
width: one_line_width,
|
|
..shape
|
|
};
|
|
|
|
let tactic =
|
|
definitive_tactic(&item_vec,
|
|
ListTactic::LimitedHorizontalVertical(context.config.fn_call_width()),
|
|
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, placeholder @ Some(..)) => {
|
|
item_vec[args.len() - 1].item = placeholder;
|
|
}
|
|
(true, _, _) => {
|
|
item_vec[args.len() - 1].item = orig_last;
|
|
}
|
|
(false, _, _) => {}
|
|
}
|
|
|
|
let mut fmt = ListFormatting {
|
|
tactic: tactic,
|
|
separator: ",",
|
|
trailing_separator: if force_trailing_comma {
|
|
SeparatorTactic::Always
|
|
} else if context.inside_macro || context.config.fn_call_style() == IndentStyle::Visual ||
|
|
args.len() <= 1 {
|
|
SeparatorTactic::Never
|
|
} else {
|
|
context.config.trailing_comma()
|
|
},
|
|
shape: one_line_shape,
|
|
ends_with_newline: false,
|
|
config: context.config,
|
|
};
|
|
|
|
let one_line_budget = min(one_line_width, context.config.fn_call_width());
|
|
let almost_no_newline =
|
|
item_vec
|
|
.iter()
|
|
.rev()
|
|
.skip(1)
|
|
.all(|item| item.item.as_ref().map_or(false, |s| !s.contains('\n')));
|
|
let extendable = almost_no_newline &&
|
|
item_vec.iter().fold(0, |acc, item| {
|
|
acc + item.item.as_ref().map_or(0, |s| 2 + first_line_width(s))
|
|
}) <= one_line_budget + 2;
|
|
|
|
let result = write_list(&item_vec, &fmt);
|
|
let last_char_is_not_comma = result
|
|
.as_ref()
|
|
.map_or(false, |r| r.chars().last().unwrap_or(' ') != ',');
|
|
match result {
|
|
// If arguments do not fit in a single line and do not contain newline,
|
|
// try to put it on the next line. Try this only when we are in block mode
|
|
// and not rewriting macro.
|
|
Some(ref s) if use_block_indent(context) && !context.inside_macro &&
|
|
((!can_be_overflowed(context, args) && last_char_is_not_comma &&
|
|
s.contains('\n')) ||
|
|
first_line_width(s) > one_line_budget) => {
|
|
fmt.trailing_separator = SeparatorTactic::Vertical;
|
|
fmt.tactic = DefinitiveListTactic::Vertical;
|
|
write_list(&item_vec, &fmt).map(|rw| (false, rw))
|
|
}
|
|
rewrite @ _ => {
|
|
rewrite.map(|rw| (extendable && (last_char_is_not_comma || force_trailing_comma), rw))
|
|
}
|
|
}
|
|
}
|
|
|
|
fn use_block_indent(context: &RewriteContext) -> bool {
|
|
context.config.fn_call_style() == IndentStyle::Block || context.use_block
|
|
}
|
|
|
|
fn can_be_overflowed(context: &RewriteContext, args: &[ptr::P<ast::Expr>]) -> bool {
|
|
match args.last().map(|x| &x.node) {
|
|
Some(&ast::ExprKind::Match(..)) => {
|
|
(use_block_indent(context) && args.len() == 1) ||
|
|
(context.config.fn_call_style() == IndentStyle::Visual && args.len() > 1)
|
|
}
|
|
Some(&ast::ExprKind::Block(..)) |
|
|
Some(&ast::ExprKind::Closure(..)) => {
|
|
use_block_indent(context) ||
|
|
context.config.fn_call_style() == IndentStyle::Visual && args.len() > 1
|
|
}
|
|
Some(&ast::ExprKind::Call(..)) |
|
|
Some(&ast::ExprKind::Mac(..)) |
|
|
Some(&ast::ExprKind::Struct(..)) => use_block_indent(context) && args.len() == 1,
|
|
Some(&ast::ExprKind::Tup(..)) => use_block_indent(context),
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
fn is_extendable(args: &[ptr::P<ast::Expr>]) -> bool {
|
|
if args.len() == 1 {
|
|
match args[0].node {
|
|
ast::ExprKind::Block(..) |
|
|
ast::ExprKind::Call(..) |
|
|
ast::ExprKind::Closure(..) |
|
|
ast::ExprKind::Match(..) |
|
|
ast::ExprKind::Mac(..) |
|
|
ast::ExprKind::Struct(..) |
|
|
ast::ExprKind::Tup(..) => true,
|
|
_ => false,
|
|
}
|
|
} else if args.len() > 1 {
|
|
match args[args.len() - 1].node {
|
|
ast::ExprKind::Block(..) |
|
|
ast::ExprKind::Closure(..) |
|
|
ast::ExprKind::Tup(..) => true,
|
|
_ => false,
|
|
}
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
fn wrap_args_with_parens(context: &RewriteContext,
|
|
args_str: &str,
|
|
is_extendable: bool,
|
|
shape: Shape,
|
|
nested_shape: Shape)
|
|
-> String {
|
|
if !use_block_indent(context) || (context.inside_macro && !args_str.contains('\n')) ||
|
|
is_extendable {
|
|
if context.config.spaces_within_parens() && args_str.len() > 0 {
|
|
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))
|
|
}
|
|
}
|
|
|
|
fn rewrite_paren(context: &RewriteContext, subexpr: &ast::Expr, shape: Shape) -> Option<String> {
|
|
debug!("rewrite_paren, shape: {:?}", shape);
|
|
// 1 is for opening paren, 2 is for opening+closing, we want to keep the closing
|
|
// paren on the same line as the subexpr.
|
|
let sub_shape = try_opt!(shape.sub_width(2)).visual_indent(1);
|
|
let subexpr_str = subexpr.rewrite(context, sub_shape);
|
|
debug!("rewrite_paren, subexpr_str: `{:?}`", subexpr_str);
|
|
|
|
subexpr_str.map(|s| if context.config.spaces_within_parens() && s.len() > 0 {
|
|
format!("( {} )", s)
|
|
} else {
|
|
format!("({})", s)
|
|
})
|
|
}
|
|
|
|
fn rewrite_index(expr: &ast::Expr,
|
|
index: &ast::Expr,
|
|
context: &RewriteContext,
|
|
shape: Shape)
|
|
-> Option<String> {
|
|
let expr_str = try_opt!(expr.rewrite(context, shape));
|
|
|
|
let (lbr, rbr) = if context.config.spaces_within_square_brackets() {
|
|
("[ ", " ]")
|
|
} else {
|
|
("[", "]")
|
|
};
|
|
|
|
let offset = expr_str.len() + lbr.len();
|
|
if let Some(index_shape) = shape.visual_indent(offset).sub_width(offset + rbr.len()) {
|
|
if let Some(index_str) = index.rewrite(context, index_shape) {
|
|
return Some(format!("{}{}{}{}", expr_str, lbr, index_str, rbr));
|
|
}
|
|
}
|
|
|
|
let indent = shape.indent.block_indent(&context.config);
|
|
let indent = indent.to_string(&context.config);
|
|
// FIXME this is not right, since we don't take into account that shape.width
|
|
// might be reduced from max_width by something on the right.
|
|
let budget = try_opt!(context
|
|
.config
|
|
.max_width()
|
|
.checked_sub(indent.len() + lbr.len() + rbr.len()));
|
|
let index_str = try_opt!(index.rewrite(context, Shape::legacy(budget, shape.indent)));
|
|
Some(format!("{}\n{}{}{}{}", expr_str, indent, lbr, index_str, rbr))
|
|
}
|
|
|
|
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 = try_opt!(shape.sub_width(2));
|
|
let path_str = try_opt!(rewrite_path(context, PathContext::Expr, None, path, path_shape));
|
|
|
|
if fields.len() == 0 && base.is_none() {
|
|
return Some(format!("{} {{}}", path_str));
|
|
}
|
|
|
|
let field_iter = fields
|
|
.into_iter()
|
|
.map(StructLitField::Regular)
|
|
.chain(base.into_iter().map(StructLitField::Base));
|
|
|
|
// Foo { a: Foo } - indent is +3, width is -5.
|
|
let (h_shape, v_shape) = try_opt!(struct_lit_shape(shape, context, path_str.len() + 3, 2));
|
|
|
|
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, try_opt!(v_shape.sub_width(1)))
|
|
}
|
|
StructLitField::Base(expr) => {
|
|
// 2 = ..
|
|
expr.rewrite(context, try_opt!(v_shape.shrink_left(2)))
|
|
.map(|s| format!("..{}", s))
|
|
}
|
|
};
|
|
|
|
let items = itemize_list(context.codemap,
|
|
field_iter,
|
|
"}",
|
|
span_lo,
|
|
span_hi,
|
|
rewrite,
|
|
context.codemap.span_after(span, "{"),
|
|
span.hi);
|
|
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());
|
|
|
|
let fields_str = try_opt!(write_list(&item_vec, &fmt));
|
|
let fields_str = if context.config.struct_lit_style() == IndentStyle::Block &&
|
|
(fields_str.contains('\n') ||
|
|
context.config.struct_lit_multiline_style() ==
|
|
MultilineStyle::ForceMulti ||
|
|
fields_str.len() > h_shape.map(|s| s.width).unwrap_or(0)) {
|
|
format!("\n{}{}\n{}",
|
|
v_shape.indent.to_string(context.config),
|
|
fields_str,
|
|
shape.indent.to_string(context.config))
|
|
} else {
|
|
// One liner or visual indent.
|
|
format!(" {} ", fields_str)
|
|
};
|
|
|
|
Some(format!("{} {{{}}}", path_str, fields_str))
|
|
|
|
// FIXME if context.config.struct_lit_style() == Visual, but we run out
|
|
// of space, we should fall back to BlockIndent.
|
|
}
|
|
|
|
pub fn type_annotation_separator(config: &Config) -> &str {
|
|
colon_spaces(config.space_before_type_annotation(),
|
|
config.space_after_type_annotation_colon())
|
|
}
|
|
|
|
fn rewrite_field(context: &RewriteContext, field: &ast::Field, shape: Shape) -> Option<String> {
|
|
let name = &field.ident.node.to_string();
|
|
if field.is_shorthand {
|
|
Some(name.to_string())
|
|
} else {
|
|
let separator = type_annotation_separator(context.config);
|
|
let overhead = name.len() + separator.len();
|
|
let mut expr_shape = try_opt!(shape.sub_width(overhead));
|
|
expr_shape.offset += overhead;
|
|
let expr = field.expr.rewrite(context, expr_shape);
|
|
|
|
let mut attrs_str = try_opt!((*field.attrs).rewrite(context, shape));
|
|
if !attrs_str.is_empty() {
|
|
attrs_str.push_str(&format!("\n{}", shape.indent.to_string(context.config)));
|
|
};
|
|
|
|
match expr {
|
|
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_fn_call_style(context: &RewriteContext,
|
|
shape: Shape,
|
|
overhead: usize,
|
|
offset: usize)
|
|
-> Option<Shape> {
|
|
if use_block_indent(context) {
|
|
Some(shape.block().block_indent(context.config.tab_spaces()))
|
|
} else {
|
|
shape.visual_indent(offset).sub_width(overhead)
|
|
}
|
|
}
|
|
|
|
pub fn rewrite_tuple_type<'a, I>(context: &RewriteContext,
|
|
mut items: I,
|
|
span: Span,
|
|
shape: Shape)
|
|
-> Option<String>
|
|
where I: ExactSizeIterator,
|
|
<I as Iterator>::Item: Deref,
|
|
<I::Item as Deref>::Target: Rewrite + Spanned + 'a
|
|
{
|
|
// In case of length 1, need a trailing comma
|
|
debug!("rewrite_tuple_type {:?}", shape);
|
|
if items.len() == 1 {
|
|
// 3 = "(" + ",)"
|
|
let nested_shape = try_opt!(shape.sub_width(3)).visual_indent(1);
|
|
return items
|
|
.next()
|
|
.unwrap()
|
|
.rewrite(context, nested_shape)
|
|
.map(|s| if context.config.spaces_within_parens() {
|
|
format!("( {}, )", s)
|
|
} else {
|
|
format!("({},)", s)
|
|
});
|
|
}
|
|
|
|
let list_lo = context.codemap.span_after(span, "(");
|
|
let nested_shape = try_opt!(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));
|
|
let list_str = try_opt!(format_item_list(items, nested_shape, context.config));
|
|
|
|
if context.config.spaces_within_parens() && list_str.len() > 0 {
|
|
Some(format!("( {} )", list_str))
|
|
} else {
|
|
Some(format!("({})", list_str))
|
|
}
|
|
}
|
|
|
|
pub fn rewrite_tuple(context: &RewriteContext,
|
|
items: &[ptr::P<ast::Expr>],
|
|
span: Span,
|
|
shape: Shape)
|
|
-> Option<String> {
|
|
debug!("rewrite_tuple {:?}", shape);
|
|
// Use old `rewrite_tuple`
|
|
if context.config.fn_call_style() == IndentStyle::Visual {
|
|
return rewrite_tuple_type(context, items.iter().map(|x| &**x), span, shape);
|
|
}
|
|
|
|
// We use the same rule as funcation call for rewriting tuple.
|
|
// 1 = ","
|
|
rewrite_call_inner(context,
|
|
&String::new(),
|
|
items,
|
|
span,
|
|
shape,
|
|
items.len() == 1)
|
|
.ok()
|
|
}
|
|
|
|
pub fn rewrite_unary_prefix<R: Rewrite>(context: &RewriteContext,
|
|
prefix: &str,
|
|
rewrite: &R,
|
|
shape: Shape)
|
|
-> Option<String> {
|
|
rewrite
|
|
.rewrite(context, try_opt!(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, try_opt!(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 => "=".to_owned(),
|
|
};
|
|
|
|
// 1 = space between lhs and operator.
|
|
let lhs_shape = try_opt!(shape.sub_width(operator_str.len() + 1));
|
|
let lhs_str = format!("{} {}",
|
|
try_opt!(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>>(context: &RewriteContext,
|
|
lhs: S,
|
|
ex: &ast::Expr,
|
|
shape: Shape)
|
|
-> Option<String> {
|
|
let mut result = lhs.into();
|
|
let last_line_width = last_line_width(&result) -
|
|
if result.contains('\n') {
|
|
shape.indent.width()
|
|
} else {
|
|
0
|
|
};
|
|
// 1 = space between operator and rhs.
|
|
let orig_shape = try_opt!(shape.block_indent(0).offset_left(last_line_width + 1));
|
|
let rhs = match ex.node {
|
|
ast::ExprKind::Mac(ref mac) => {
|
|
match rewrite_macro(mac, None, context, orig_shape, MacroPosition::Expression) {
|
|
None if !context.snippet(ex.span).contains("\n") => {
|
|
context.snippet(ex.span).rewrite(context, orig_shape)
|
|
}
|
|
rhs @ _ => rhs,
|
|
}
|
|
}
|
|
_ => ex.rewrite(context, orig_shape),
|
|
};
|
|
|
|
fn count_line_breaks(src: &str) -> usize {
|
|
src.chars().filter(|&x| x == '\n').count()
|
|
}
|
|
|
|
match rhs {
|
|
Some(ref new_str) if count_line_breaks(new_str) < 2 => {
|
|
result.push(' ');
|
|
result.push_str(new_str);
|
|
}
|
|
_ => {
|
|
// Expression did not fit on the same line as the identifier or is
|
|
// at least three lines big. Try splitting the line and see
|
|
// if that works better.
|
|
let new_shape = try_opt!(shape.block_left(context.config.tab_spaces()));
|
|
let new_rhs = ex.rewrite(context, new_shape);
|
|
|
|
// FIXME: DRY!
|
|
match (rhs, new_rhs) {
|
|
(Some(ref orig_rhs), Some(ref replacement_rhs))
|
|
if count_line_breaks(orig_rhs) > count_line_breaks(replacement_rhs) + 1 ||
|
|
(orig_rhs.rewrite(context, shape).is_none() &&
|
|
replacement_rhs.rewrite(context, new_shape).is_some()) => {
|
|
result.push_str(&format!("\n{}", new_shape.indent.to_string(context.config)));
|
|
result.push_str(replacement_rhs);
|
|
}
|
|
(None, Some(ref final_rhs)) => {
|
|
result.push_str(&format!("\n{}", new_shape.indent.to_string(context.config)));
|
|
result.push_str(final_rhs);
|
|
}
|
|
(None, None) => return None,
|
|
(Some(ref orig_rhs), _) => {
|
|
result.push(' ');
|
|
result.push_str(orig_rhs);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
Some(result)
|
|
}
|
|
|
|
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)
|
|
}
|