117 lines
4.1 KiB
Rust
117 lines
4.1 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 visitor::FmtVisitor;
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use lists::{write_list, ListFormatting, SeparatorTactic, ListTactic};
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use utils::format_visibility;
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use syntax::ast;
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use syntax::parse::token;
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use syntax::print::pprust;
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// TODO remove empty lists (if they're even possible)
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// TODO (some day) remove unused imports, expand globs, compress many single imports into a list import
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fn rewrite_single_use_list(path_str: String, vpi: ast::PathListItem, vis: &str) -> String {
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if let ast::PathListItem_::PathListIdent{ name, .. } = vpi.node {
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let name_str = token::get_ident(name).to_string();
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if path_str.len() == 0 {
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format!("{}use {};", vis, name_str)
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} else {
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format!("{}use {}::{};", vis, path_str, name_str)
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}
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} else {
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if path_str.len() != 0 {
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format!("{}use {};", vis, path_str)
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} else {
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// This catches the import: use {self}, which is a compiler error, so we just
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// leave it alone.
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format!("{}use {{self}};", vis)
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}
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}
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}
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impl<'a> FmtVisitor<'a> {
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// Basically just pretty prints a multi-item import.
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pub fn rewrite_use_list(&mut self,
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block_indent: usize,
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one_line_budget: usize, // excluding indentation
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multi_line_budget: usize,
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path: &ast::Path,
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path_list: &[ast::PathListItem],
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visibility: ast::Visibility) -> String {
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let path_str = pprust::path_to_string(path);
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let vis = format_visibility(visibility);
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if path_list.len() == 1 {
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return rewrite_single_use_list(path_str, path_list[0], vis);
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}
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// 2 = ::
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let path_separation_w = if path_str.len() > 0 { 2 } else { 0 };
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// 5 = "use " + {
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let indent = path_str.len() + 5 + path_separation_w + vis.len();
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// 2 = } + ;
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let used_width = indent + 2;
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// Break as early as possible when we've blown our budget.
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let remaining_line_budget = if used_width > one_line_budget {
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0
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} else {
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one_line_budget - used_width
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};
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let remaining_multi_budget = if used_width > multi_line_budget {
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0
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} else {
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multi_line_budget - used_width
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};
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let fmt = ListFormatting {
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tactic: ListTactic::Mixed,
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separator: ",",
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trailing_separator: SeparatorTactic::Never,
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indent: block_indent + indent,
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h_width: remaining_line_budget,
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v_width: remaining_multi_budget,
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};
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// TODO handle any comments inbetween items.
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// If `self` is in the list, put it first.
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let head = if path_list.iter().any(|vpi|
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if let ast::PathListItem_::PathListMod{ .. } = vpi.node {
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true
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} else {
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false
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}
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) {
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Some(("self".to_owned(), String::new()))
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} else {
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None
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};
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let items: Vec<_> = head.into_iter().chain(path_list.iter().filter_map(|vpi| {
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match vpi.node {
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ast::PathListItem_::PathListIdent{ name, .. } => {
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Some((token::get_ident(name).to_string(), String::new()))
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}
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// Skip `self`, because we added it above.
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ast::PathListItem_::PathListMod{ .. } => None,
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}
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})).collect();
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if path_str.len() == 0 {
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format!("{}use {{{}}};", vis, write_list(&items, &fmt))
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} else {
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format!("{}use {}::{{{}}};", vis, path_str, write_list(&items, &fmt))
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}
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}
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}
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