1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 use visitor::FmtVisitor;
12 use lists::{write_list, ListFormatting, SeparatorTactic, ListTactic};
15 use syntax::parse::token;
16 use syntax::print::pprust;
19 // TODO remove empty lists (if they're even possible)
20 // TODO (some day) remove unused imports, expand globs, compress many single imports into a list import
22 fn rewrite_single_use_list(path_str: String, vpi: ast::PathListItem, vis: &str) -> String {
23 if let ast::PathListItem_::PathListIdent{ name, .. } = vpi.node {
24 let name_str = token::get_ident(name).to_string();
25 if path_str.len() == 0 {
26 format!("{}use {};", vis, name_str)
28 format!("{}use {}::{};", vis, path_str, name_str)
31 if path_str.len() != 0 {
32 format!("{}use {};", vis, path_str)
34 // This catches the import: use {self}, which is a compiler error, so we just
36 format!("{}use {{self}};", vis)
41 impl<'a> FmtVisitor<'a> {
42 // Basically just pretty prints a multi-item import.
43 pub fn rewrite_use_list(&mut self,
45 one_line_budget: usize, // excluding indentation
46 multi_line_budget: usize,
48 path_list: &[ast::PathListItem],
49 visibility: ast::Visibility) -> String {
50 let path_str = pprust::path_to_string(path);
52 let vis = match visibility {
53 ast::Public => "pub ",
57 if path_list.len() == 1 {
58 return rewrite_single_use_list(path_str, path_list[0], vis);
62 let path_separation_w = if path_str.len() > 0 { 2 } else { 0 };
64 let indent = path_str.len() + 5 + path_separation_w + vis.len();
67 let used_width = indent + 2;
69 // Break as early as possible when we've blown our budget.
70 let remaining_line_budget = if used_width > one_line_budget {
73 one_line_budget - used_width
75 let remaining_multi_budget = if used_width > multi_line_budget {
78 multi_line_budget - used_width
81 let fmt = ListFormatting {
82 tactic: ListTactic::Mixed,
84 trailing_separator: SeparatorTactic::Never,
85 indent: block_indent + indent,
86 h_width: remaining_line_budget,
87 v_width: remaining_multi_budget,
90 // TODO handle any comments inbetween items.
91 // If `self` is in the list, put it first.
92 let head = if path_list.iter().any(|vpi|
93 if let ast::PathListItem_::PathListMod{ .. } = vpi.node {
99 Some(("self".to_owned(), String::new()))
104 let items: Vec<_> = head.into_iter().chain(path_list.iter().filter_map(|vpi| {
106 ast::PathListItem_::PathListIdent{ name, .. } => {
107 Some((token::get_ident(name).to_string(), String::new()))
109 // Skip `self`, because we added it above.
110 ast::PathListItem_::PathListMod{ .. } => None,
113 if path_str.len() == 0 {
114 format!("{}use {{{}}};", vis, write_list(&items, &fmt))
116 format!("{}use {}::{{{}}};", vis, path_str, write_list(&items, &fmt))