1619 lines
63 KiB
Rust
1619 lines
63 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;
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use std::borrow::Borrow;
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use std::mem::swap;
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use {Indent, Spanned};
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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_fn_args};
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use string::{StringFormat, rewrite_string};
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use utils::{span_after, extra_offset, last_line_width, wrap_str, binary_search, first_line_width,
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semicolon_for_stmt};
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use visitor::FmtVisitor;
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use config::{StructLitStyle, MultilineStyle};
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use comment::{FindUncommented, rewrite_comment, contains_comment};
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use types::rewrite_path;
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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;
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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::visit::Visitor;
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impl Rewrite for ast::Expr {
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fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
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match self.node {
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ast::Expr_::ExprVec(ref expr_vec) => {
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rewrite_array(expr_vec.iter().map(|e| &**e),
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mk_sp(span_after(self.span, "[", context.codemap), self.span.hi),
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context,
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width,
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offset)
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}
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ast::Expr_::ExprLit(ref l) => {
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match l.node {
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ast::Lit_::LitStr(_, ast::StrStyle::CookedStr) => {
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rewrite_string_lit(context, l.span, width, offset)
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}
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_ => {
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wrap_str(context.snippet(self.span),
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context.config.max_width,
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width,
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offset)
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}
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}
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}
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ast::Expr_::ExprCall(ref callee, ref args) => {
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let inner_span = mk_sp(callee.span.hi, self.span.hi);
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rewrite_call(context, &**callee, args, inner_span, width, offset)
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}
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ast::Expr_::ExprParen(ref subexpr) => rewrite_paren(context, subexpr, width, offset),
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ast::Expr_::ExprBinary(ref op, ref lhs, ref rhs) => {
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rewrite_binary_op(context, op, lhs, rhs, width, offset)
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}
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ast::Expr_::ExprUnary(ref op, ref subexpr) => {
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rewrite_unary_op(context, op, subexpr, width, offset)
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}
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ast::Expr_::ExprStruct(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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self.span,
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width,
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offset)
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}
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ast::Expr_::ExprTup(ref items) => {
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rewrite_tuple(context, items, self.span, width, offset)
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}
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ast::Expr_::ExprWhile(ref cond, ref block, label) => {
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Loop::new_while(None, cond, block, label).rewrite(context, width, offset)
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}
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ast::Expr_::ExprWhileLet(ref pat, ref cond, ref block, label) => {
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Loop::new_while(Some(pat), cond, block, label).rewrite(context, width, offset)
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}
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ast::Expr_::ExprForLoop(ref pat, ref cond, ref block, label) => {
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Loop::new_for(pat, cond, block, label).rewrite(context, width, offset)
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}
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ast::Expr_::ExprLoop(ref block, label) => {
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Loop::new_loop(block, label).rewrite(context, width, offset)
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}
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ast::Expr_::ExprBlock(ref block) => block.rewrite(context, width, offset),
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ast::Expr_::ExprIf(ref cond, ref if_block, ref else_block) => {
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rewrite_if_else(context,
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cond,
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if_block,
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else_block.as_ref().map(|e| &**e),
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None,
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width,
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offset,
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true)
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}
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ast::Expr_::ExprIfLet(ref pat, ref cond, ref if_block, ref else_block) => {
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rewrite_if_else(context,
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cond,
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if_block,
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else_block.as_ref().map(|e| &**e),
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Some(pat),
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width,
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offset,
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true)
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}
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ast::Expr_::ExprMatch(ref cond, ref arms) => {
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rewrite_match(context, cond, arms, width, offset, self.span)
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}
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ast::Expr_::ExprPath(ref qself, ref path) => {
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rewrite_path(context, true, qself.as_ref(), path, width, offset)
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}
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ast::Expr_::ExprAssign(ref lhs, ref rhs) => {
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rewrite_assignment(context, lhs, rhs, None, width, offset)
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}
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ast::Expr_::ExprAssignOp(ref op, ref lhs, ref rhs) => {
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rewrite_assignment(context, lhs, rhs, Some(op), width, offset)
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}
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ast::Expr_::ExprAgain(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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Some(format!("continue{}", id_str))
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}
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ast::Expr_::ExprBreak(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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Some(format!("break{}", id_str))
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}
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ast::Expr_::ExprClosure(capture, ref fn_decl, ref body) => {
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rewrite_closure(capture, fn_decl, body, self.span, context, width, offset)
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}
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ast::Expr_::ExprField(..) |
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ast::Expr_::ExprTupField(..) |
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ast::Expr_::ExprMethodCall(..) => rewrite_chain(self, context, width, offset),
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ast::Expr_::ExprMac(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, context, width, offset).or_else(|| {
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wrap_str(context.snippet(self.span),
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context.config.max_width,
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width,
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offset)
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})
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}
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ast::Expr_::ExprRet(None) => {
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wrap_str("return".to_owned(), context.config.max_width, width, offset)
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}
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ast::Expr_::ExprRet(Some(ref expr)) => {
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rewrite_unary_prefix(context, "return ", &**expr, width, offset)
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}
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ast::Expr_::ExprBox(ref expr) => {
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rewrite_unary_prefix(context, "box ", &**expr, width, offset)
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}
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ast::Expr_::ExprAddrOf(mutability, ref expr) => {
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rewrite_expr_addrof(context, mutability, expr, width, offset)
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}
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ast::Expr_::ExprCast(ref expr, ref ty) => {
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rewrite_pair(&**expr, &**ty, "", " as ", "", context, width, offset)
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}
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ast::Expr_::ExprIndex(ref expr, ref index) => {
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rewrite_pair(&**expr, &**index, "", "[", "]", context, width, offset)
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}
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ast::Expr_::ExprRepeat(ref expr, ref repeats) => {
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rewrite_pair(&**expr, &**repeats, "[", "; ", "]", context, width, offset)
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}
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ast::Expr_::ExprRange(Some(ref lhs), Some(ref rhs)) => {
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rewrite_pair(&**lhs, &**rhs, "", "..", "", context, width, offset)
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}
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ast::Expr_::ExprRange(None, Some(ref rhs)) => {
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rewrite_unary_prefix(context, "..", &**rhs, width, offset)
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}
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ast::Expr_::ExprRange(Some(ref lhs), None) => {
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Some(format!("{}..",
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try_opt!(lhs.rewrite(context,
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try_opt!(width.checked_sub(2)),
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offset))))
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}
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ast::Expr_::ExprRange(None, None) => {
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if width >= 2 {
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Some("..".into())
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} else {
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None
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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::Expr_::ExprInPlace(..) |
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ast::Expr_::ExprInlineAsm(..) => {
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wrap_str(context.snippet(self.span),
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context.config.max_width,
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width,
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offset)
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}
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}
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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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width: usize,
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offset: Indent)
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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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let max_width = try_opt!(width.checked_sub(prefix.len() + infix.len() + suffix.len()));
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binary_search(1, max_width, |lhs_budget| {
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let lhs_offset = offset + prefix.len();
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let lhs_str = match lhs.rewrite(context, lhs_budget, lhs_offset) {
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Some(result) => result,
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None => return Err(Ordering::Greater),
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};
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let last_line_width = last_line_width(&lhs_str);
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let rhs_budget = match max_width.checked_sub(last_line_width) {
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Some(b) => b,
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None => return Err(Ordering::Less),
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};
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let rhs_indent = offset + last_line_width + prefix.len() + infix.len();
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let rhs_str = match rhs.rewrite(context, rhs_budget, rhs_indent) {
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Some(result) => result,
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None => return Err(Ordering::Less),
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};
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Ok(format!("{}{}{}{}{}", prefix, lhs_str, infix, rhs_str, suffix))
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})
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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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width: usize,
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offset: Indent)
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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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// 2 for brackets;
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let offset = offset + 1;
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let inner_context = &RewriteContext { block_indent: offset, ..*context };
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let max_item_width = try_opt!(width.checked_sub(2));
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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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// 1 = [
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|item| item.rewrite(&inner_context, max_item_width, offset),
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span.lo,
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span.hi)
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.collect::<Vec<_>>();
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let has_long_item = try_opt!(items.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 = if has_long_item || items.iter().any(ListItem::is_multiline) {
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definitive_tactic(&items, ListTactic::HorizontalVertical, max_item_width)
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} else {
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DefinitiveListTactic::Mixed
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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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indent: offset,
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width: max_item_width,
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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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Some(format!("[{}]", list_str))
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}
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// This functions is pretty messy because of the wrapping and unwrapping of
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// expressions into and from blocks. See rust issue #27872.
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fn rewrite_closure(capture: ast::CaptureClause,
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fn_decl: &ast::FnDecl,
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body: &ast::Block,
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span: Span,
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context: &RewriteContext,
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width: usize,
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offset: Indent)
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-> Option<String> {
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let mover = if capture == ast::CaptureClause::CaptureByValue {
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"move "
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} else {
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""
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};
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let offset = offset + mover.len();
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// 4 = "|| {".len(), which is overconservative when the closure consists of
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// a single expression.
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let budget = try_opt!(width.checked_sub(4 + mover.len()));
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// 1 = |
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let argument_offset = offset + 1;
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let ret_str = try_opt!(fn_decl.output.rewrite(context, budget, argument_offset));
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// 1 = space between arguments and return type.
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let horizontal_budget = budget.checked_sub(ret_str.len() + 1).unwrap_or(0);
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let arg_items = itemize_list(context.codemap,
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fn_decl.inputs.iter(),
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"|",
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|arg| span_lo_for_arg(arg),
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|arg| span_hi_for_arg(arg),
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|arg| arg.rewrite(context, budget, argument_offset),
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span_after(span, "|", context.codemap),
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body.span.lo);
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let item_vec = arg_items.collect::<Vec<_>>();
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let tactic = definitive_tactic(&item_vec, ListTactic::HorizontalVertical, horizontal_budget);
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let budget = match tactic {
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DefinitiveListTactic::Horizontal => horizontal_budget,
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_ => budget,
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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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indent: argument_offset,
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width: budget,
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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(&item_vec, &fmt));
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let mut prefix = format!("{}|{}|", mover, list_str);
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if !ret_str.is_empty() {
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if prefix.contains('\n') {
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prefix.push('\n');
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prefix.push_str(&argument_offset.to_string(context.config));
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} else {
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prefix.push(' ');
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}
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prefix.push_str(&ret_str);
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}
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// Try to format closure body as a single line expression without braces.
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if is_simple_block(body, context.codemap) && !prefix.contains('\n') {
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let (spacer, closer) = if ret_str.is_empty() {
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(" ", "")
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} else {
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(" { ", " }")
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};
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let expr = body.expr.as_ref().unwrap();
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// All closure bodies are blocks in the eyes of the AST, but we may not
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// want to unwrap them when they only contain a single expression.
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let inner_expr = match expr.node {
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ast::Expr_::ExprBlock(ref inner) if inner.stmts.is_empty() && inner.expr.is_some() &&
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inner.rules ==
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ast::BlockCheckMode::DefaultBlock => {
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inner.expr.as_ref().unwrap()
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}
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_ => expr,
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};
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let extra_offset = extra_offset(&prefix, offset) + spacer.len();
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let budget = try_opt!(width.checked_sub(extra_offset + closer.len()));
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let rewrite = inner_expr.rewrite(context, budget, offset + extra_offset);
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// Checks if rewrite succeeded and fits on a single line.
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let accept_rewrite = rewrite.as_ref().map(|result| !result.contains('\n')).unwrap_or(false);
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if accept_rewrite {
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return Some(format!("{}{}{}{}", prefix, spacer, rewrite.unwrap(), closer));
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}
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}
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// We couldn't format the closure body as a single line expression; fall
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// back to block formatting.
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let body_rewrite = body.expr
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.as_ref()
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.and_then(|body_expr| {
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if let ast::Expr_::ExprBlock(ref inner) = body_expr.node {
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Some(inner.rewrite(&context, 2, Indent::empty()))
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} else {
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None
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}
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})
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.unwrap_or_else(|| body.rewrite(&context, 2, Indent::empty()));
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Some(format!("{} {}", prefix, try_opt!(body_rewrite)))
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}
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fn nop_block_collapse(block_str: Option<String>, budget: usize) -> Option<String> {
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block_str.map(|block_str| {
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if block_str.starts_with("{") && budget >= 2 &&
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(block_str[1..].find(|c: char| !c.is_whitespace()).unwrap() == block_str.len() - 2) {
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"{}".to_owned()
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} else {
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block_str.to_owned()
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}
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})
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}
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impl Rewrite for ast::Block {
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fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
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let user_str = context.snippet(self.span);
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if user_str == "{}" && width >= 2 {
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return Some(user_str);
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}
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let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config, None);
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visitor.block_indent = context.block_indent;
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let prefix = match self.rules {
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ast::BlockCheckMode::UnsafeBlock(..) => {
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let snippet = context.snippet(self.span);
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let open_pos = try_opt!(snippet.find_uncommented("{"));
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visitor.last_pos = self.span.lo + BytePos(open_pos as u32);
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// Extract comment between unsafe and block start.
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let trimmed = &snippet[6..open_pos].trim();
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let prefix = if !trimmed.is_empty() {
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// 9 = "unsafe {".len(), 7 = "unsafe ".len()
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let budget = try_opt!(width.checked_sub(9));
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format!("unsafe {} ",
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try_opt!(rewrite_comment(trimmed,
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true,
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budget,
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offset + 7,
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context.config)))
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} else {
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"unsafe ".to_owned()
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};
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if is_simple_block(self, context.codemap) && prefix.len() < width {
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let body = self.expr
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.as_ref()
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.unwrap()
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.rewrite(context, width - prefix.len(), offset);
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if let Some(ref expr_str) = body {
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let result = format!("{}{{ {} }}", prefix, expr_str);
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if result.len() <= width && !result.contains('\n') {
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return Some(result);
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}
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}
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}
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prefix
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}
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ast::BlockCheckMode::DefaultBlock => {
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visitor.last_pos = self.span.lo;
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String::new()
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}
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};
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visitor.visit_block(self);
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Some(format!("{}{}", prefix, visitor.buffer))
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}
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}
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impl Rewrite for ast::Stmt {
|
|
fn rewrite(&self, context: &RewriteContext, _width: usize, offset: Indent) -> Option<String> {
|
|
match self.node {
|
|
ast::Stmt_::StmtDecl(ref decl, _) => {
|
|
if let ast::Decl_::DeclLocal(ref local) = decl.node {
|
|
local.rewrite(context, context.config.max_width, offset)
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
ast::Stmt_::StmtExpr(ref ex, _) | ast::Stmt_::StmtSemi(ref ex, _) => {
|
|
let suffix = if semicolon_for_stmt(self) {
|
|
";"
|
|
} else {
|
|
""
|
|
};
|
|
|
|
ex.rewrite(context,
|
|
context.config.max_width - offset.width() - suffix.len(),
|
|
offset)
|
|
.map(|s| s + suffix)
|
|
}
|
|
ast::Stmt_::StmtMac(..) => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
// Abstraction over for, while and loop expressions
|
|
struct Loop<'a> {
|
|
cond: Option<&'a ast::Expr>,
|
|
block: &'a ast::Block,
|
|
label: Option<ast::Ident>,
|
|
pat: Option<&'a ast::Pat>,
|
|
keyword: &'a str,
|
|
matcher: &'a str,
|
|
connector: &'a str,
|
|
}
|
|
|
|
impl<'a> Loop<'a> {
|
|
fn new_loop(block: &'a ast::Block, label: Option<ast::Ident>) -> Loop<'a> {
|
|
Loop {
|
|
cond: None,
|
|
block: block,
|
|
label: label,
|
|
pat: None,
|
|
keyword: "loop",
|
|
matcher: "",
|
|
connector: "",
|
|
}
|
|
}
|
|
|
|
fn new_while(pat: Option<&'a ast::Pat>,
|
|
cond: &'a ast::Expr,
|
|
block: &'a ast::Block,
|
|
label: Option<ast::Ident>)
|
|
-> Loop<'a> {
|
|
Loop {
|
|
cond: Some(cond),
|
|
block: block,
|
|
label: label,
|
|
pat: pat,
|
|
keyword: "while ",
|
|
matcher: match pat {
|
|
Some(..) => "let ",
|
|
None => "",
|
|
},
|
|
connector: " =",
|
|
}
|
|
}
|
|
|
|
fn new_for(pat: &'a ast::Pat,
|
|
cond: &'a ast::Expr,
|
|
block: &'a ast::Block,
|
|
label: Option<ast::Ident>)
|
|
-> Loop<'a> {
|
|
Loop {
|
|
cond: Some(cond),
|
|
block: block,
|
|
label: label,
|
|
pat: Some(pat),
|
|
keyword: "for ",
|
|
matcher: "",
|
|
connector: " in",
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a> Rewrite for Loop<'a> {
|
|
fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
|
|
let label_string = rewrite_label(self.label);
|
|
// 2 = " {".len()
|
|
let inner_width = try_opt!(width.checked_sub(self.keyword.len() + 2 + label_string.len()));
|
|
let inner_offset = offset + self.keyword.len() + label_string.len();
|
|
|
|
let pat_expr_string = match self.cond {
|
|
Some(cond) => {
|
|
try_opt!(rewrite_pat_expr(context,
|
|
self.pat,
|
|
cond,
|
|
self.matcher,
|
|
self.connector,
|
|
inner_width,
|
|
inner_offset))
|
|
}
|
|
None => String::new(),
|
|
};
|
|
|
|
// FIXME: this drops any comment between "loop" and the block.
|
|
self.block
|
|
.rewrite(context, width, offset)
|
|
.map(|result| {
|
|
format!("{}{}{} {}",
|
|
label_string,
|
|
self.keyword,
|
|
pat_expr_string,
|
|
result)
|
|
})
|
|
}
|
|
}
|
|
|
|
fn rewrite_label(label: Option<ast::Ident>) -> String {
|
|
match label {
|
|
Some(ident) => format!("{}: ", ident),
|
|
None => "".to_owned(),
|
|
}
|
|
}
|
|
|
|
// Rewrites if-else blocks. If let Some(_) = pat, the expression is
|
|
// treated as an if-let-else expression.
|
|
fn rewrite_if_else(context: &RewriteContext,
|
|
cond: &ast::Expr,
|
|
if_block: &ast::Block,
|
|
else_block_opt: Option<&ast::Expr>,
|
|
pat: Option<&ast::Pat>,
|
|
width: usize,
|
|
offset: Indent,
|
|
allow_single_line: bool)
|
|
-> Option<String> {
|
|
// 3 = "if ", 2 = " {"
|
|
let pat_expr_string = try_opt!(rewrite_pat_expr(context,
|
|
pat,
|
|
cond,
|
|
"let ",
|
|
" =",
|
|
try_opt!(width.checked_sub(3 + 2)),
|
|
offset + 3));
|
|
|
|
// Try to format if-else on single line.
|
|
if allow_single_line && context.config.single_line_if_else {
|
|
let trial = single_line_if_else(context, &pat_expr_string, if_block, else_block_opt, width);
|
|
|
|
if trial.is_some() {
|
|
return trial;
|
|
}
|
|
}
|
|
|
|
let if_block_string = try_opt!(if_block.rewrite(context, width, offset));
|
|
let mut result = format!("if {} {}", pat_expr_string, if_block_string);
|
|
|
|
if let Some(else_block) = else_block_opt {
|
|
let rewrite = match else_block.node {
|
|
// If the else expression is another if-else expression, prevent it
|
|
// from being formatted on a single line.
|
|
ast::Expr_::ExprIfLet(ref pat, ref cond, ref if_block, ref else_block) => {
|
|
rewrite_if_else(context,
|
|
cond,
|
|
if_block,
|
|
else_block.as_ref().map(|e| &**e),
|
|
Some(pat),
|
|
width,
|
|
offset,
|
|
false)
|
|
}
|
|
ast::Expr_::ExprIf(ref cond, ref if_block, ref else_block) => {
|
|
rewrite_if_else(context,
|
|
cond,
|
|
if_block,
|
|
else_block.as_ref().map(|e| &**e),
|
|
None,
|
|
width,
|
|
offset,
|
|
false)
|
|
}
|
|
_ => else_block.rewrite(context, width, offset),
|
|
};
|
|
|
|
result.push_str(" else ");
|
|
result.push_str(&&try_opt!(rewrite));
|
|
}
|
|
|
|
Some(result)
|
|
}
|
|
|
|
fn single_line_if_else(context: &RewriteContext,
|
|
pat_expr_str: &str,
|
|
if_node: &ast::Block,
|
|
else_block_opt: Option<&ast::Expr>,
|
|
width: usize)
|
|
-> Option<String> {
|
|
let else_block = try_opt!(else_block_opt);
|
|
let fixed_cost = "if { } else { }".len();
|
|
|
|
if let ast::ExprBlock(ref else_node) = else_block.node {
|
|
if !is_simple_block(if_node, 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 if_expr = if_node.expr.as_ref().unwrap();
|
|
let if_str = try_opt!(if_expr.rewrite(context, new_width, Indent::empty()));
|
|
|
|
let new_width = try_opt!(new_width.checked_sub(if_str.len()));
|
|
let else_expr = else_node.expr.as_ref().unwrap();
|
|
let else_str = try_opt!(else_expr.rewrite(context, new_width, Indent::empty()));
|
|
|
|
// FIXME: this check shouldn't be necessary. Rewrites should either fail
|
|
// or wrap to a newline when the object does not fit the width.
|
|
let fits_line = fixed_cost + pat_expr_str.len() + if_str.len() + else_str.len() <= width;
|
|
|
|
if fits_line && !if_str.contains('\n') && !else_str.contains('\n') {
|
|
return Some(format!("if {} {{ {} }} else {{ {} }}",
|
|
pat_expr_str,
|
|
if_str,
|
|
else_str));
|
|
}
|
|
}
|
|
|
|
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.is_empty() && block.expr.is_some() && !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.is_empty() || (block.stmts.len() == 1 && block.expr.is_none())) &&
|
|
!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.expr.is_none() && !block_contains_comment(block, codemap)
|
|
}
|
|
|
|
fn is_unsafe_block(block: &ast::Block) -> bool {
|
|
if let ast::BlockCheckMode::UnsafeBlock(..) = 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,
|
|
width: usize,
|
|
arm_indent: Indent,
|
|
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
|
|
// TODO 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,
|
|
width,
|
|
arm_indent,
|
|
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],
|
|
width: usize,
|
|
offset: Indent,
|
|
span: Span)
|
|
-> Option<String> {
|
|
if arms.is_empty() {
|
|
return None;
|
|
}
|
|
|
|
// `match `cond` {`
|
|
let cond_budget = try_opt!(width.checked_sub(8));
|
|
let cond_str = try_opt!(cond.rewrite(context, cond_budget, offset + 6));
|
|
let mut result = format!("match {} {{", cond_str);
|
|
|
|
let nested_context = context.nested_context();
|
|
let arm_indent = nested_context.block_indent;
|
|
let arm_indent_str = arm_indent.to_string(context.config);
|
|
|
|
let open_brace_pos = span_after(mk_sp(cond.span.hi, arm_start_pos(&arms[0])),
|
|
"{",
|
|
context.codemap);
|
|
|
|
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,
|
|
width,
|
|
arm_indent,
|
|
&arm_indent_str));
|
|
result.push_str(&comment);
|
|
result.push('\n');
|
|
result.push_str(&arm_indent_str);
|
|
|
|
let arm_str = arm.rewrite(&nested_context,
|
|
context.config.max_width - arm_indent.width(),
|
|
arm_indent);
|
|
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(&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,
|
|
width,
|
|
arm_indent,
|
|
&arm_indent_str));
|
|
result.push_str(&comment);
|
|
result.push('\n');
|
|
result.push_str(&context.block_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(body: &ast::Expr) -> &'static str {
|
|
if let ast::ExprBlock(ref block) = body.node {
|
|
if let ast::DefaultBlock = block.rules {
|
|
""
|
|
} else {
|
|
","
|
|
}
|
|
} else {
|
|
","
|
|
}
|
|
}
|
|
|
|
// Match arms.
|
|
impl Rewrite for ast::Arm {
|
|
fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
|
|
let &ast::Arm { ref attrs, ref pats, ref guard, ref body } = self;
|
|
let indent_str = offset.to_string(context.config);
|
|
|
|
// 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,
|
|
None);
|
|
attr_visitor.block_indent = context.block_indent;
|
|
attr_visitor.last_pos = attrs[0].span.lo;
|
|
if attr_visitor.visit_attrs(attrs) {
|
|
// Attributes included a skip instruction.
|
|
let snippet = context.snippet(mk_sp(attrs[0].span.lo, body.span.hi));
|
|
return Some(snippet);
|
|
}
|
|
attr_visitor.format_missing(pats[0].span.lo);
|
|
attr_visitor.buffer.to_string()
|
|
} else {
|
|
String::new()
|
|
};
|
|
|
|
// Patterns
|
|
// 5 = ` => {`
|
|
let pat_budget = try_opt!(width.checked_sub(5));
|
|
let pat_strs = try_opt!(pats.iter()
|
|
.map(|p| p.rewrite(context, pat_budget, offset))
|
|
.collect::<Option<Vec<_>>>());
|
|
|
|
let mut total_width = pat_strs.iter().fold(0, |a, p| a + p.len());
|
|
// Add ` | `.len().
|
|
total_width += (pat_strs.len() - 1) * 3;
|
|
|
|
let mut vertical = total_width > pat_budget || pat_strs.iter().any(|p| p.contains('\n'));
|
|
if !vertical && context.config.take_source_hints {
|
|
// If the patterns were previously stacked, keep them stacked.
|
|
let pat_span = mk_sp(pats[0].span.lo, pats[pats.len() - 1].span.hi);
|
|
let pat_str = context.snippet(pat_span);
|
|
vertical = pat_str.contains('\n');
|
|
}
|
|
|
|
let pats_width = if vertical {
|
|
pat_strs.last().unwrap().len()
|
|
} else {
|
|
total_width
|
|
};
|
|
|
|
let mut pats_str = String::new();
|
|
for p in pat_strs {
|
|
if !pats_str.is_empty() {
|
|
if vertical {
|
|
pats_str.push_str(" |\n");
|
|
pats_str.push_str(&indent_str);
|
|
} else {
|
|
pats_str.push_str(" | ");
|
|
}
|
|
}
|
|
pats_str.push_str(&p);
|
|
}
|
|
|
|
let guard_str = try_opt!(rewrite_guard(context, guard, width, offset, pats_width));
|
|
|
|
let pats_str = format!("{}{}", pats_str, guard_str);
|
|
// Where the next text can start.
|
|
let mut line_start = last_line_width(&pats_str);
|
|
if !pats_str.contains('\n') {
|
|
line_start += offset.width();
|
|
}
|
|
|
|
let body = match **body {
|
|
ast::Expr { node: ast::ExprBlock(ref block), .. } if !is_unsafe_block(block) &&
|
|
is_simple_block(block,
|
|
context.codemap) &&
|
|
context.config.wrap_match_arms => {
|
|
block.expr.as_ref().map(|e| &**e).unwrap()
|
|
}
|
|
ref x => x,
|
|
};
|
|
|
|
let comma = arm_comma(body);
|
|
|
|
// Let's try and get the arm body on the same line as the condition.
|
|
// 4 = ` => `.len()
|
|
if context.config.max_width > line_start + comma.len() + 4 {
|
|
let budget = context.config.max_width - line_start - comma.len() - 4;
|
|
let offset = Indent::new(offset.block_indent, line_start + 4 - offset.block_indent);
|
|
let rewrite = nop_block_collapse(body.rewrite(context, budget, offset), budget);
|
|
|
|
match rewrite {
|
|
Some(ref body_str) if !body_str.contains('\n') || !context.config.wrap_match_arms ||
|
|
comma.is_empty() => {
|
|
return Some(format!("{}{} => {}{}",
|
|
attr_str.trim_left(),
|
|
pats_str,
|
|
body_str,
|
|
comma));
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
|
|
// FIXME: we're doing a second rewrite of the expr; This may not be
|
|
// necessary.
|
|
let body_budget = try_opt!(width.checked_sub(context.config.tab_spaces));
|
|
let indent = context.block_indent.block_indent(context.config);
|
|
let inner_context = &RewriteContext { block_indent: indent, ..*context };
|
|
let next_line_body = try_opt!(nop_block_collapse(body.rewrite(inner_context,
|
|
body_budget,
|
|
indent),
|
|
body_budget));
|
|
let indent_str = offset.block_indent(context.config).to_string(context.config);
|
|
let (body_prefix, body_suffix) = if context.config.wrap_match_arms {
|
|
(" {", "}")
|
|
} else {
|
|
("", "")
|
|
};
|
|
|
|
Some(format!("{}{} =>{}\n{}{}\n{}{}",
|
|
attr_str.trim_left(),
|
|
pats_str,
|
|
body_prefix,
|
|
indent_str,
|
|
next_line_body,
|
|
offset.to_string(context.config),
|
|
body_suffix))
|
|
}
|
|
}
|
|
|
|
// The `if ...` guard on a match arm.
|
|
fn rewrite_guard(context: &RewriteContext,
|
|
guard: &Option<ptr::P<ast::Expr>>,
|
|
width: usize,
|
|
offset: Indent,
|
|
// 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 < width {
|
|
let cond_str = guard.rewrite(context, width - overhead, offset + pattern_width + 4);
|
|
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 = context.config.tab_spaces + 4 + 5;
|
|
if overhead < width {
|
|
let cond_str = guard.rewrite(context,
|
|
width - overhead,
|
|
offset.block_indent(context.config));
|
|
if let Some(cond_str) = cond_str {
|
|
return Some(format!("\n{}if {}",
|
|
offset.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,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
let pat_offset = offset + matcher.len();
|
|
let mut result = match pat {
|
|
Some(pat) => {
|
|
let pat_budget = try_opt!(width.checked_sub(connector.len() + matcher.len()));
|
|
let pat_string = try_opt!(pat.rewrite(context, pat_budget, pat_offset));
|
|
format!("{}{}{}", matcher, pat_string, connector)
|
|
}
|
|
None => String::new(),
|
|
};
|
|
|
|
// Consider only the last line of the pat string.
|
|
let extra_offset = extra_offset(&result, offset);
|
|
|
|
// The expression may (partionally) fit on the current line.
|
|
if width > extra_offset + 1 {
|
|
let spacer = if pat.is_some() {
|
|
" "
|
|
} else {
|
|
""
|
|
};
|
|
|
|
let expr_rewrite = expr.rewrite(context,
|
|
width - extra_offset - spacer.len(),
|
|
offset + extra_offset + spacer.len());
|
|
|
|
if let Some(expr_string) = expr_rewrite {
|
|
result.push_str(spacer);
|
|
result.push_str(&expr_string);
|
|
return Some(result);
|
|
}
|
|
}
|
|
|
|
// The expression won't fit on the current line, jump to next.
|
|
result.push('\n');
|
|
result.push_str(&pat_offset.to_string(context.config));
|
|
|
|
let expr_rewrite = expr.rewrite(context,
|
|
context.config.max_width - pat_offset.width(),
|
|
pat_offset);
|
|
result.push_str(&&try_opt!(expr_rewrite));
|
|
|
|
Some(result)
|
|
}
|
|
|
|
fn rewrite_string_lit(context: &RewriteContext,
|
|
span: Span,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
if !context.config.format_strings {
|
|
return Some(context.snippet(span));
|
|
}
|
|
|
|
let fmt = StringFormat {
|
|
opener: "\"",
|
|
closer: "\"",
|
|
line_start: " ",
|
|
line_end: "\\",
|
|
width: width,
|
|
offset: offset,
|
|
trim_end: false,
|
|
config: context.config,
|
|
};
|
|
|
|
let string_lit = context.snippet(span);
|
|
let str_lit = &string_lit[1..string_lit.len() - 1]; // Remove the quote characters.
|
|
|
|
rewrite_string(str_lit, &fmt)
|
|
}
|
|
|
|
pub fn rewrite_call<R>(context: &RewriteContext,
|
|
callee: &R,
|
|
args: &[ptr::P<ast::Expr>],
|
|
span: Span,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String>
|
|
where R: Rewrite
|
|
{
|
|
let closure = |callee_max_width| {
|
|
rewrite_call_inner(context, callee, callee_max_width, args, span, width, offset)
|
|
};
|
|
|
|
// 2 is for parens
|
|
let max_width = try_opt!(width.checked_sub(2));
|
|
binary_search(1, max_width, closure)
|
|
}
|
|
|
|
fn rewrite_call_inner<R>(context: &RewriteContext,
|
|
callee: &R,
|
|
max_callee_width: usize,
|
|
args: &[ptr::P<ast::Expr>],
|
|
span: Span,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Result<String, Ordering>
|
|
where R: Rewrite
|
|
{
|
|
let callee = callee.borrow();
|
|
// FIXME using byte lens instead of char lens (and probably all over the
|
|
// place too)
|
|
let callee_str = match callee.rewrite(context, max_callee_width, offset) {
|
|
Some(string) => {
|
|
if !string.contains('\n') && string.len() > max_callee_width {
|
|
panic!("{:?} {}", string, max_callee_width);
|
|
} else {
|
|
string
|
|
}
|
|
}
|
|
None => return Err(Ordering::Greater),
|
|
};
|
|
|
|
let span_lo = span_after(span, "(", context.codemap);
|
|
let span = mk_sp(span_lo, span.hi);
|
|
|
|
let extra_offset = extra_offset(&callee_str, offset);
|
|
// 2 is for parens.
|
|
let remaining_width = match width.checked_sub(extra_offset + 2) {
|
|
Some(str) => str,
|
|
None => return Err(Ordering::Greater),
|
|
};
|
|
let offset = offset + extra_offset + 1;
|
|
let arg_count = args.len();
|
|
let block_indent = if arg_count == 1 {
|
|
context.block_indent
|
|
} else {
|
|
offset
|
|
};
|
|
let inner_context = &RewriteContext { block_indent: block_indent, ..*context };
|
|
|
|
let items = itemize_list(context.codemap,
|
|
args.iter(),
|
|
")",
|
|
|item| item.span.lo,
|
|
|item| item.span.hi,
|
|
|item| item.rewrite(&inner_context, remaining_width, offset),
|
|
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 = match args.last().map(|x| &x.node) {
|
|
Some(&ast::Expr_::ExprClosure(..)) |
|
|
Some(&ast::Expr_::ExprBlock(..)) if arg_count > 1 => true,
|
|
_ => false,
|
|
} && context.config.chains_overflow_last;
|
|
|
|
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 inner_context = &RewriteContext { block_indent: context.block_indent, ..*context };
|
|
let rewrite = args.last().unwrap().rewrite(&inner_context, remaining_width, offset);
|
|
|
|
if let Some(rewrite) = rewrite {
|
|
let rewrite_first_line = Some(rewrite[..first_line_width(&rewrite)].to_owned());
|
|
placeholder = Some(rewrite);
|
|
|
|
swap(&mut item_vec[arg_count - 1].item, &mut orig_last);
|
|
item_vec[arg_count - 1].item = rewrite_first_line;
|
|
}
|
|
}
|
|
|
|
let tactic = definitive_tactic(&item_vec,
|
|
ListTactic::LimitedHorizontalVertical(context.config
|
|
.fn_call_width),
|
|
remaining_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[arg_count - 1].item = placeholder;
|
|
}
|
|
(true, _, _) => {
|
|
item_vec[arg_count - 1].item = orig_last;
|
|
}
|
|
(false, _, _) => {}
|
|
}
|
|
|
|
let fmt = ListFormatting {
|
|
tactic: tactic,
|
|
separator: ",",
|
|
trailing_separator: SeparatorTactic::Never,
|
|
indent: offset,
|
|
width: width,
|
|
ends_with_newline: false,
|
|
config: context.config,
|
|
};
|
|
|
|
let list_str = match write_list(&item_vec, &fmt) {
|
|
Some(str) => str,
|
|
None => return Err(Ordering::Less),
|
|
};
|
|
|
|
Ok(format!("{}({})", callee_str, list_str))
|
|
}
|
|
|
|
fn rewrite_paren(context: &RewriteContext,
|
|
subexpr: &ast::Expr,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
debug!("rewrite_paren, width: {}, offset: {:?}", width, offset);
|
|
// 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 subexpr_str = subexpr.rewrite(context, try_opt!(width.checked_sub(2)), offset + 1);
|
|
debug!("rewrite_paren, subexpr_str: `{:?}`", subexpr_str);
|
|
subexpr_str.map(|s| format!("({})", s))
|
|
}
|
|
|
|
fn rewrite_struct_lit<'a>(context: &RewriteContext,
|
|
path: &ast::Path,
|
|
fields: &'a [ast::Field],
|
|
base: Option<&'a ast::Expr>,
|
|
span: Span,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
debug!("rewrite_struct_lit: width {}, offset {:?}", width, offset);
|
|
assert!(!fields.is_empty() || base.is_some());
|
|
|
|
enum StructLitField<'a> {
|
|
Regular(&'a ast::Field),
|
|
Base(&'a ast::Expr),
|
|
}
|
|
|
|
// 2 = " {".len()
|
|
let path_budget = try_opt!(width.checked_sub(2));
|
|
let path_str = try_opt!(rewrite_path(context, true, None, path, path_budget, offset));
|
|
|
|
// Foo { a: Foo } - indent is +3, width is -5.
|
|
let h_budget = width.checked_sub(path_str.len() + 5).unwrap_or(0);
|
|
let (indent, v_budget) = match context.config.struct_lit_style {
|
|
StructLitStyle::Visual => (offset + path_str.len() + 3, h_budget),
|
|
StructLitStyle::Block => {
|
|
// If we are all on one line, then we'll ignore the indent, and we
|
|
// have a smaller budget.
|
|
let indent = context.block_indent.block_indent(context.config);
|
|
let v_budget = context.config.max_width.checked_sub(indent.width()).unwrap_or(0);
|
|
(indent, v_budget)
|
|
}
|
|
};
|
|
|
|
let field_iter = fields.into_iter()
|
|
.map(StructLitField::Regular)
|
|
.chain(base.into_iter().map(StructLitField::Base));
|
|
|
|
let inner_context = &RewriteContext { block_indent: indent, ..*context };
|
|
|
|
let items = itemize_list(context.codemap,
|
|
field_iter,
|
|
"}",
|
|
|item| {
|
|
match *item {
|
|
StructLitField::Regular(ref field) => field.span.lo,
|
|
StructLitField::Base(ref 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)
|
|
}
|
|
}
|
|
},
|
|
|item| {
|
|
match *item {
|
|
StructLitField::Regular(ref field) => field.span.hi,
|
|
StructLitField::Base(ref expr) => expr.span.hi,
|
|
}
|
|
},
|
|
|item| {
|
|
match *item {
|
|
StructLitField::Regular(ref field) => {
|
|
rewrite_field(inner_context, &field, v_budget, indent)
|
|
}
|
|
StructLitField::Base(ref expr) => {
|
|
// 2 = ..
|
|
expr.rewrite(inner_context,
|
|
try_opt!(v_budget.checked_sub(2)),
|
|
indent + 2)
|
|
.map(|s| format!("..{}", s))
|
|
}
|
|
}
|
|
},
|
|
span_after(span, "{", context.codemap),
|
|
span.hi);
|
|
let item_vec = items.collect::<Vec<_>>();
|
|
|
|
let tactic = {
|
|
let mut prelim_tactic = match (context.config.struct_lit_style, fields.len()) {
|
|
(StructLitStyle::Visual, 1) => ListTactic::HorizontalVertical,
|
|
_ => context.config.struct_lit_multiline_style.to_list_tactic(),
|
|
};
|
|
|
|
if prelim_tactic == ListTactic::HorizontalVertical && fields.len() > 1 {
|
|
prelim_tactic = ListTactic::LimitedHorizontalVertical(context.config.struct_lit_width);
|
|
}
|
|
|
|
definitive_tactic(&item_vec, prelim_tactic, h_budget)
|
|
};
|
|
|
|
let budget = match tactic {
|
|
DefinitiveListTactic::Horizontal => h_budget,
|
|
_ => v_budget,
|
|
};
|
|
|
|
let ends_with_newline = context.config.struct_lit_style != StructLitStyle::Visual &&
|
|
tactic == DefinitiveListTactic::Vertical;
|
|
|
|
let fmt = ListFormatting {
|
|
tactic: tactic,
|
|
separator: ",",
|
|
trailing_separator: if base.is_some() {
|
|
SeparatorTactic::Never
|
|
} else {
|
|
context.config.struct_lit_trailing_comma
|
|
},
|
|
indent: indent,
|
|
width: budget,
|
|
ends_with_newline: ends_with_newline,
|
|
config: context.config,
|
|
};
|
|
let fields_str = try_opt!(write_list(&item_vec, &fmt));
|
|
|
|
let format_on_newline = || {
|
|
let inner_indent = context.block_indent
|
|
.block_indent(context.config)
|
|
.to_string(context.config);
|
|
let outer_indent = context.block_indent.to_string(context.config);
|
|
Some(format!("{} {{\n{}{}\n{}}}",
|
|
path_str,
|
|
inner_indent,
|
|
fields_str,
|
|
outer_indent))
|
|
};
|
|
|
|
match (context.config.struct_lit_style,
|
|
context.config.struct_lit_multiline_style) {
|
|
(StructLitStyle::Block, _) if fields_str.contains('\n') || fields_str.len() > h_budget => {
|
|
format_on_newline()
|
|
}
|
|
(StructLitStyle::Block, MultilineStyle::ForceMulti) => format_on_newline(),
|
|
_ => 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.
|
|
}
|
|
|
|
fn rewrite_field(context: &RewriteContext,
|
|
field: &ast::Field,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
let name = &field.ident.node.to_string();
|
|
let overhead = name.len() + 2;
|
|
let expr = field.expr.rewrite(context,
|
|
try_opt!(width.checked_sub(overhead)),
|
|
offset + overhead);
|
|
expr.map(|s| format!("{}: {}", name, s))
|
|
}
|
|
|
|
pub fn rewrite_tuple<'a, R>(context: &RewriteContext,
|
|
items: &'a [ptr::P<R>],
|
|
span: Span,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String>
|
|
where R: Rewrite + Spanned + 'a
|
|
{
|
|
debug!("rewrite_tuple_lit: width: {}, offset: {:?}", width, offset);
|
|
let indent = offset + 1;
|
|
// In case of length 1, need a trailing comma
|
|
if items.len() == 1 {
|
|
// 3 = "(" + ",)"
|
|
let budget = try_opt!(width.checked_sub(3));
|
|
return items[0].rewrite(context, budget, indent).map(|s| format!("({},)", s));
|
|
}
|
|
|
|
let items = itemize_list(context.codemap,
|
|
items.iter(),
|
|
")",
|
|
|item| item.span().lo,
|
|
|item| item.span().hi,
|
|
|item| {
|
|
let inner_width = try_opt!(context.config
|
|
.max_width
|
|
.checked_sub(indent.width() +
|
|
1));
|
|
item.rewrite(context, inner_width, indent)
|
|
},
|
|
span.lo + BytePos(1), // Remove parens
|
|
span.hi - BytePos(1));
|
|
let budget = try_opt!(width.checked_sub(2));
|
|
let list_str = try_opt!(format_fn_args(items, budget, indent, context.config));
|
|
|
|
Some(format!("({})", list_str))
|
|
}
|
|
|
|
fn rewrite_binary_op(context: &RewriteContext,
|
|
op: &ast::BinOp,
|
|
lhs: &ast::Expr,
|
|
rhs: &ast::Expr,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
// FIXME: format comments between operands and operator
|
|
|
|
let operator_str = context.snippet(op.span);
|
|
|
|
// Get "full width" rhs and see if it fits on the current line. This
|
|
// usually works fairly well since it tends to place operands of
|
|
// operations with high precendence close together.
|
|
let rhs_result = try_opt!(rhs.rewrite(context, width, offset));
|
|
|
|
// Second condition is needed in case of line break not caused by a
|
|
// shortage of space, but by end-of-line comments, for example.
|
|
// Note that this is non-conservative, but its just to see if it's even
|
|
// worth trying to put everything on one line.
|
|
if rhs_result.len() + 2 + operator_str.len() < width && !rhs_result.contains('\n') {
|
|
// 1 = space between lhs expr and operator
|
|
if let Some(mut result) = lhs.rewrite(context, width - 1 - operator_str.len(), offset) {
|
|
result.push(' ');
|
|
result.push_str(&operator_str);
|
|
result.push(' ');
|
|
|
|
let remaining_width = width.checked_sub(last_line_width(&result)).unwrap_or(0);
|
|
|
|
if rhs_result.len() <= remaining_width {
|
|
result.push_str(&rhs_result);
|
|
return Some(result);
|
|
}
|
|
|
|
if let Some(rhs_result) = rhs.rewrite(context, remaining_width, offset + result.len()) {
|
|
if rhs_result.len() <= remaining_width {
|
|
result.push_str(&rhs_result);
|
|
return Some(result);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// We have to use multiple lines.
|
|
|
|
// Re-evaluate the lhs because we have more space now:
|
|
let budget = try_opt!(context.config
|
|
.max_width
|
|
.checked_sub(offset.width() + 1 + operator_str.len()));
|
|
Some(format!("{} {}\n{}{}",
|
|
try_opt!(lhs.rewrite(context, budget, offset)),
|
|
operator_str,
|
|
offset.to_string(context.config),
|
|
rhs_result))
|
|
}
|
|
|
|
pub fn rewrite_unary_prefix<R: Rewrite>(context: &RewriteContext,
|
|
prefix: &str,
|
|
rewrite: &R,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
rewrite.rewrite(context,
|
|
try_opt!(width.checked_sub(prefix.len())),
|
|
offset + prefix.len())
|
|
.map(|r| format!("{}{}", prefix, r))
|
|
}
|
|
|
|
fn rewrite_unary_op(context: &RewriteContext,
|
|
op: &ast::UnOp,
|
|
expr: &ast::Expr,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
// For some reason, an UnOp is not spanned like BinOp!
|
|
let operator_str = match *op {
|
|
ast::UnOp::UnDeref => "*",
|
|
ast::UnOp::UnNot => "!",
|
|
ast::UnOp::UnNeg => "-",
|
|
};
|
|
rewrite_unary_prefix(context, operator_str, expr, width, offset)
|
|
}
|
|
|
|
fn rewrite_assignment(context: &RewriteContext,
|
|
lhs: &ast::Expr,
|
|
rhs: &ast::Expr,
|
|
op: Option<&ast::BinOp>,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
let operator_str = match op {
|
|
Some(op) => context.snippet(op.span),
|
|
None => "=".to_owned(),
|
|
};
|
|
|
|
// 1 = space between lhs and operator.
|
|
let max_width = try_opt!(width.checked_sub(operator_str.len() + 1));
|
|
let lhs_str = format!("{} {}",
|
|
try_opt!(lhs.rewrite(context, max_width, offset)),
|
|
operator_str);
|
|
|
|
rewrite_assign_rhs(&context, lhs_str, rhs, width, offset)
|
|
}
|
|
|
|
// 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,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
let mut result = lhs.into();
|
|
let last_line_width = last_line_width(&result) -
|
|
if result.contains('\n') {
|
|
offset.width()
|
|
} else {
|
|
0
|
|
};
|
|
// 1 = space between operator and rhs.
|
|
let max_width = try_opt!(width.checked_sub(last_line_width + 1));
|
|
let rhs = ex.rewrite(&context, max_width, offset + last_line_width + 1);
|
|
|
|
match rhs {
|
|
Some(new_str) => {
|
|
result.push(' ');
|
|
result.push_str(&new_str)
|
|
}
|
|
None => {
|
|
// Expression did not fit on the same line as the identifier. Retry
|
|
// on the next line.
|
|
let new_offset = offset.block_indent(context.config);
|
|
result.push_str(&format!("\n{}", new_offset.to_string(context.config)));
|
|
|
|
// FIXME: we probably should related max_width to width instead of
|
|
// config.max_width where is the 1 coming from anyway?
|
|
let max_width = try_opt!(context.config.max_width.checked_sub(new_offset.width() + 1));
|
|
let inner_context = context.nested_context();
|
|
let rhs = ex.rewrite(&inner_context, max_width, new_offset);
|
|
|
|
result.push_str(&&try_opt!(rhs));
|
|
}
|
|
}
|
|
|
|
Some(result)
|
|
}
|
|
|
|
fn rewrite_expr_addrof(context: &RewriteContext,
|
|
mutability: ast::Mutability,
|
|
expr: &ast::Expr,
|
|
width: usize,
|
|
offset: Indent)
|
|
-> Option<String> {
|
|
let operator_str = match mutability {
|
|
ast::Mutability::MutImmutable => "&",
|
|
ast::Mutability::MutMutable => "&mut ",
|
|
};
|
|
rewrite_unary_prefix(context, operator_str, expr, width, offset)
|
|
}
|