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, ListItem, ListFormatting, SeparatorTactic, ListTactic};
13 use utils::format_visibility;
16 use syntax::parse::token;
17 use syntax::print::pprust;
19 // TODO (some day) remove unused imports, expand globs, compress many single imports into a list import
21 fn rewrite_single_use_list(path_str: String, vpi: ast::PathListItem, vis: &str) -> String {
22 if let ast::PathListItem_::PathListIdent{ name, .. } = vpi.node {
23 let name_str = token::get_ident(name).to_string();
24 if path_str.len() == 0 {
25 format!("{}use {};", vis, name_str)
27 format!("{}use {}::{};", vis, path_str, name_str)
30 if path_str.len() != 0 {
31 format!("{}use {};", vis, path_str)
33 // This catches the import: use {self}, which is a compiler error, so we just
35 format!("{}use {{self}};", vis)
40 impl<'a> FmtVisitor<'a> {
41 // Basically just pretty prints a multi-item import.
42 // Returns None when the import can be removed.
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) -> Option<String> {
50 let path_str = pprust::path_to_string(path);
51 let vis = format_visibility(visibility);
53 match path_list.len() {
55 1 => return Some(rewrite_single_use_list(path_str, path_list[0], vis)),
60 let path_separation_w = if path_str.len() > 0 { 2 } else { 0 };
62 let indent = path_str.len() + 5 + path_separation_w + vis.len();
65 let used_width = indent + 2;
67 // Break as early as possible when we've blown our budget.
68 let remaining_line_budget = one_line_budget.checked_sub(used_width).unwrap_or(0);
69 let remaining_multi_budget = multi_line_budget.checked_sub(used_width).unwrap_or(0);
71 let fmt = ListFormatting {
72 tactic: ListTactic::Mixed,
74 trailing_separator: SeparatorTactic::Never,
75 indent: block_indent + indent,
76 h_width: remaining_line_budget,
77 v_width: remaining_multi_budget,
81 // TODO handle any comments inbetween items.
82 // If `self` is in the list, put it first.
83 let head = if path_list.iter().any(|vpi|
84 if let ast::PathListItem_::PathListMod{ .. } = vpi.node {
90 Some(ListItem::from_str("self"))
95 let items: Vec<_> = head.into_iter().chain(path_list.iter().filter_map(|vpi| {
97 ast::PathListItem_::PathListIdent{ name, .. } => {
98 Some(ListItem::from_str(token::get_ident(name).to_string()))
100 // Skip `self`, because we added it above.
101 ast::PathListItem_::PathListMod{ .. } => None,
105 Some(if path_str.len() == 0 {
106 format!("{}use {{{}}};", vis, write_list(&items, &fmt))
108 format!("{}use {}::{{{}}};", vis, path_str, write_list(&items, &fmt))