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.
13 use syntax::codemap::{self, BytePos, Span};
14 use codemap::SpanUtils;
15 use lists::{write_list, itemize_list, ListItem, ListFormatting, SeparatorTactic, definitive_tactic};
16 use types::rewrite_path;
17 use rewrite::{Rewrite, RewriteContext};
18 use visitor::FmtVisitor;
19 use std::cmp::{self, Ordering};
21 use syntax::{ast, ptr};
23 fn path_of(a: &ast::ViewPath_) -> &ast::Path {
25 ast::ViewPath_::ViewPathSimple(_, ref p) => p,
26 ast::ViewPath_::ViewPathGlob(ref p) => p,
27 ast::ViewPath_::ViewPathList(ref p, _) => p,
31 fn compare_path_segments(a: &ast::PathSegment, b: &ast::PathSegment) -> Ordering {
32 a.identifier.name.as_str().cmp(&b.identifier.name.as_str())
35 fn compare_paths(a: &ast::Path, b: &ast::Path) -> Ordering {
36 for segment in a.segments.iter().zip(b.segments.iter()) {
37 let ord = compare_path_segments(segment.0, segment.1);
38 if ord != Ordering::Equal {
42 a.segments.len().cmp(&b.segments.len())
45 fn compare_path_list_items(a: &ast::PathListItem, b: &ast::PathListItem) -> Ordering {
46 let a_name_str = &*a.node.name.name.as_str();
47 let b_name_str = &*b.node.name.name.as_str();
48 let name_ordering = if a_name_str == "self" {
49 if b_name_str == "self" {
55 if b_name_str == "self" {
58 a_name_str.cmp(&b_name_str)
61 if name_ordering == Ordering::Equal {
65 Some(b_rename) => a_rename.name.as_str().cmp(&b_rename.name.as_str()),
66 None => Ordering::Greater,
69 None => Ordering::Less,
76 fn compare_path_list_item_lists(a_items: &Vec<ast::PathListItem>,
77 b_items: &Vec<ast::PathListItem>)
79 let mut a = a_items.clone();
80 let mut b = b_items.clone();
81 a.sort_by(|a, b| compare_path_list_items(a, b));
82 b.sort_by(|a, b| compare_path_list_items(a, b));
83 for comparison_pair in a.iter().zip(b.iter()) {
84 let ord = compare_path_list_items(comparison_pair.0, comparison_pair.1);
85 if ord != Ordering::Equal {
92 fn compare_view_path_types(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering {
93 use syntax::ast::ViewPath_::*;
95 (&ViewPathSimple(..), &ViewPathSimple(..)) => Ordering::Equal,
96 (&ViewPathSimple(..), _) => Ordering::Less,
97 (&ViewPathGlob(_), &ViewPathSimple(..)) => Ordering::Greater,
98 (&ViewPathGlob(_), &ViewPathGlob(_)) => Ordering::Equal,
99 (&ViewPathGlob(_), &ViewPathList(..)) => Ordering::Less,
100 (&ViewPathList(_, ref a_items), &ViewPathList(_, ref b_items)) => {
101 compare_path_list_item_lists(a_items, b_items)
103 (&ViewPathList(..), _) => Ordering::Greater,
107 fn compare_view_paths(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering {
108 match compare_paths(path_of(a), path_of(b)) {
109 Ordering::Equal => compare_view_path_types(a, b),
114 fn compare_use_items(a: &ast::Item, b: &ast::Item) -> Option<Ordering> {
115 match (&a.node, &b.node) {
116 (&ast::ItemKind::Use(ref a_vp), &ast::ItemKind::Use(ref b_vp)) => {
117 Some(compare_view_paths(&a_vp.node, &b_vp.node))
123 // TODO (some day) remove unused imports, expand globs, compress many single
124 // imports into a list import.
126 impl Rewrite for ast::ViewPath {
127 // Returns an empty string when the ViewPath is empty (like foo::bar::{})
128 fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
130 ast::ViewPath_::ViewPathList(_, ref path_list) if path_list.is_empty() => {
133 ast::ViewPath_::ViewPathList(ref path, ref path_list) => {
134 rewrite_use_list(width, offset, path, path_list, self.span, context)
136 ast::ViewPath_::ViewPathGlob(_) => {
137 // FIXME convert to list?
140 ast::ViewPath_::ViewPathSimple(ident, ref path) => {
141 let ident_str = ident.to_string();
143 let budget = try_opt!(width.checked_sub(ident_str.len() + 4));
144 let path_str = try_opt!(rewrite_path(context, false, None, path, budget, offset));
146 Some(if path.segments.last().unwrap().identifier == ident {
149 format!("{} as {}", path_str, ident_str)
156 impl<'a> FmtVisitor<'a> {
157 pub fn format_imports(&mut self, use_items: &[ptr::P<ast::Item>]) {
158 // Find the location immediately before the first use item in the run. This must not lie
159 // before the current `self.last_pos`
160 let pos_before_first_use_item = use_items.first()
162 cmp::max(self.last_pos,
163 p_i.attrs.iter().map(|attr| attr.span.lo).min().unwrap_or(p_i.span.lo))
165 .unwrap_or(self.last_pos);
166 // Construct a list of pairs, each containing a `use` item and the start of span before
168 let mut last_pos_of_prev_use_item = pos_before_first_use_item;
169 let mut ordered_use_items = use_items.iter()
171 let new_item = (&*p_i, last_pos_of_prev_use_item);
172 last_pos_of_prev_use_item = p_i.span.hi;
175 .collect::<Vec<_>>();
176 let pos_after_last_use_item = last_pos_of_prev_use_item;
177 // Order the imports by view-path & other import path properties
178 ordered_use_items.sort_by(|a, b| compare_use_items(a.0, b.0).unwrap());
179 // First, output the span before the first import
180 let prev_span_str = self.snippet(codemap::mk_sp(self.last_pos, pos_before_first_use_item));
181 // Look for purely trailing space at the start of the prefix snippet before a linefeed, or
182 // a prefix that's entirely horizontal whitespace.
183 let prefix_span_start = match prev_span_str.find('\n') {
184 Some(offset) if prev_span_str[..offset].trim().is_empty() => {
185 self.last_pos + BytePos(offset as u32)
187 None if prev_span_str.trim().is_empty() => pos_before_first_use_item,
190 // Look for indent (the line part preceding the use is all whitespace) and excise that
192 let span_end = match prev_span_str.rfind('\n') {
193 Some(offset) if prev_span_str[offset..].trim().is_empty() => {
194 self.last_pos + BytePos(offset as u32)
196 _ => pos_before_first_use_item,
199 self.last_pos = prefix_span_start;
200 self.format_missing(span_end);
201 for ordered in ordered_use_items {
202 // Fake out the formatter by setting `self.last_pos` to the appropriate location before
203 // each item before visiting it.
204 self.last_pos = ordered.1;
205 self.visit_item(ordered.0);
207 self.last_pos = pos_after_last_use_item;
210 pub fn format_import(&mut self, vis: &ast::Visibility, vp: &ast::ViewPath, span: Span) {
211 let vis = utils::format_visibility(vis);
212 let mut offset = self.block_indent;
213 offset.alignment += vis.len() + "use ".len();
215 match vp.rewrite(&self.get_context(),
216 self.config.max_width - offset.width() - 1,
218 Some(ref s) if s.is_empty() => {
219 // Format up to last newline
220 let prev_span = codemap::mk_sp(self.last_pos, source!(self, span).lo);
221 let span_end = match self.snippet(prev_span).rfind('\n') {
222 Some(offset) => self.last_pos + BytePos(offset as u32),
223 None => source!(self, span).lo,
225 self.format_missing(span_end);
226 self.last_pos = source!(self, span).hi;
229 let s = format!("{}use {};", vis, s);
230 self.format_missing_with_indent(source!(self, span).lo);
231 self.buffer.push_str(&s);
232 self.last_pos = source!(self, span).hi;
235 self.format_missing_with_indent(source!(self, span).lo);
236 self.format_missing(source!(self, span).hi);
242 fn rewrite_single_use_list(path_str: Option<String>, vpi: &ast::PathListItem) -> String {
243 let path_item_str = match path_str {
244 Some(ref path_str) if vpi.node.name.to_string() == "self" => path_str.to_owned(),
245 Some(path_str) => format!("{}::{}", path_str, vpi.node.name),
246 None => vpi.node.name.to_string(),
249 append_alias(path_item_str, vpi)
252 fn rewrite_path_item(vpi: &&ast::PathListItem) -> Option<String> {
253 Some(append_alias(vpi.node.name.to_string(), vpi))
256 fn append_alias(path_item_str: String, vpi: &ast::PathListItem) -> String {
257 match vpi.node.rename {
258 Some(rename) => format!("{} as {}", path_item_str, rename),
259 None => path_item_str,
263 // Pretty prints a multi-item import.
264 // Assumes that path_list.len() > 0.
265 pub fn rewrite_use_list(width: usize,
268 path_list: &[ast::PathListItem],
270 context: &RewriteContext)
272 // Returns a different option to distinguish `::foo` and `foo`
273 let opt_path_str = if !path.to_string().is_empty() {
274 Some(path.to_string())
275 } else if path.global {
276 // path is absolute, we return an empty String to avoid a double `::`
282 match path_list.len() {
284 1 => return Some(rewrite_single_use_list(opt_path_str, &path_list[0])),
289 let path_separation_w = if opt_path_str.is_some() { 2 } else { 0 };
291 let supp_indent = path.to_string().len() + path_separation_w + 1;
293 let remaining_width = width.checked_sub(supp_indent + 1).unwrap_or(0);
296 // Dummy value, see explanation below.
297 let mut items = vec![ListItem::from_str("")];
298 let iter = itemize_list(context.codemap,
304 context.codemap.span_after(span, "{"),
310 // We prefixed the item list with a dummy value so that we can
311 // potentially move "self" to the front of the vector without touching
312 // the rest of the items.
313 let has_self = move_self_to_front(&mut items);
314 let first_index = if has_self { 0 } else { 1 };
316 if context.config.reorder_imported_names {
317 items[1..].sort_by(|a, b| a.item.cmp(&b.item));
320 let tactic = definitive_tactic(&items[first_index..],
321 ::lists::ListTactic::Mixed,
323 let fmt = ListFormatting {
326 trailing_separator: SeparatorTactic::Never,
327 indent: offset + supp_indent,
328 // FIXME This is too conservative, and will not use all width
330 // (loose 1 column (";"))
331 width: remaining_width,
332 ends_with_newline: false,
333 config: context.config,
335 let list_str = try_opt!(write_list(&items[first_index..], &fmt));
337 Some(match opt_path_str {
338 Some(opt_path_str) => format!("{}::{{{}}}", opt_path_str, list_str),
339 None => format!("{{{}}}", list_str),
343 // Returns true when self item was found.
344 fn move_self_to_front(items: &mut Vec<ListItem>) -> bool {
345 match items.iter().position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self")) {
347 items[0] = items.remove(pos);