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};
13 use utils::format_visibility;
16 use syntax::parse::token;
17 use syntax::print::pprust;
20 // TODO remove empty lists (if they're even possible)
21 // TODO (some day) remove unused imports, expand globs, compress many single imports into a list import
23 fn rewrite_single_use_list(path_str: String, vpi: ast::PathListItem, vis: &str) -> String {
24 if let ast::PathListItem_::PathListIdent{ name, .. } = vpi.node {
25 let name_str = token::get_ident(name).to_string();
26 if path_str.len() == 0 {
27 format!("{}use {};", vis, name_str)
29 format!("{}use {}::{};", vis, path_str, name_str)
32 if path_str.len() != 0 {
33 format!("{}use {};", vis, path_str)
35 // This catches the import: use {self}, which is a compiler error, so we just
37 format!("{}use {{self}};", vis)
42 impl<'a> FmtVisitor<'a> {
43 // Basically just pretty prints a multi-item import.
44 pub fn rewrite_use_list(&mut self,
46 one_line_budget: usize, // excluding indentation
47 multi_line_budget: usize,
49 path_list: &[ast::PathListItem],
50 visibility: ast::Visibility) -> String {
51 let path_str = pprust::path_to_string(path);
52 let vis = format_visibility(visibility);
54 if path_list.len() == 1 {
55 return rewrite_single_use_list(path_str, path_list[0], vis);
59 let path_separation_w = if path_str.len() > 0 { 2 } else { 0 };
61 let indent = path_str.len() + 5 + path_separation_w + vis.len();
64 let used_width = indent + 2;
66 // Break as early as possible when we've blown our budget.
67 let remaining_line_budget = if used_width > one_line_budget {
70 one_line_budget - used_width
72 let remaining_multi_budget = if used_width > multi_line_budget {
75 multi_line_budget - used_width
78 let fmt = ListFormatting {
79 tactic: ListTactic::Mixed,
81 trailing_separator: SeparatorTactic::Never,
82 indent: block_indent + indent,
83 h_width: remaining_line_budget,
84 v_width: remaining_multi_budget,
87 // TODO handle any comments inbetween items.
88 // If `self` is in the list, put it first.
89 let head = if path_list.iter().any(|vpi|
90 if let ast::PathListItem_::PathListMod{ .. } = vpi.node {
96 Some(("self".to_owned(), String::new()))
101 let items: Vec<_> = head.into_iter().chain(path_list.iter().filter_map(|vpi| {
103 ast::PathListItem_::PathListIdent{ name, .. } => {
104 Some((token::get_ident(name).to_string(), String::new()))
106 // Skip `self`, because we added it above.
107 ast::PathListItem_::PathListMod{ .. } => None,
110 if path_str.len() == 0 {
111 format!("{}use {{{}}};", vis, write_list(&items, &fmt))
113 format!("{}use {}::{{{}}};", vis, path_str, write_list(&items, &fmt))