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()
161 .map(|p_i| cmp::max(self.last_pos, p_i.span.lo))
162 .unwrap_or(self.last_pos);
163 // Construct a list of pairs, each containing a `use` item and the start of span before
165 let mut last_pos_of_prev_use_item = pos_before_first_use_item;
166 let mut ordered_use_items = use_items.iter()
168 let new_item = (&*p_i, last_pos_of_prev_use_item);
169 last_pos_of_prev_use_item = p_i.span.hi;
172 .collect::<Vec<_>>();
173 let pos_after_last_use_item = last_pos_of_prev_use_item;
174 // Order the imports by view-path & other import path properties
175 ordered_use_items.sort_by(|a, b| compare_use_items(a.0, b.0).unwrap());
176 // First, output the span before the first import
177 let prev_span_str = self.snippet(codemap::mk_sp(self.last_pos, pos_before_first_use_item));
178 // Look for purely trailing space at the start of the prefix snippet before a linefeed, or
179 // a prefix that's entirely horizontal whitespace.
180 let prefix_span_start = match prev_span_str.find('\n') {
181 Some(offset) if prev_span_str[..offset].trim().is_empty() => {
182 self.last_pos + BytePos(offset as u32)
184 None if prev_span_str.trim().is_empty() => pos_before_first_use_item,
187 // Look for indent (the line part preceding the use is all whitespace) and excise that
189 let span_end = match prev_span_str.rfind('\n') {
190 Some(offset) if prev_span_str[offset..].trim().is_empty() => {
191 self.last_pos + BytePos(offset as u32)
193 _ => pos_before_first_use_item,
196 self.last_pos = prefix_span_start;
197 self.format_missing(span_end);
198 for ordered in ordered_use_items {
199 // Fake out the formatter by setting `self.last_pos` to the appropriate location before
200 // each item before visiting it.
201 self.last_pos = ordered.1;
202 self.visit_item(ordered.0);
204 self.last_pos = pos_after_last_use_item;
207 pub fn format_import(&mut self, vis: &ast::Visibility, vp: &ast::ViewPath, span: Span) {
208 let vis = utils::format_visibility(vis);
209 let mut offset = self.block_indent;
210 offset.alignment += vis.len() + "use ".len();
212 match vp.rewrite(&self.get_context(),
213 self.config.max_width - offset.width() - 1,
215 Some(ref s) if s.is_empty() => {
216 // Format up to last newline
217 let prev_span = codemap::mk_sp(self.last_pos, source!(self, span).lo);
218 let span_end = match self.snippet(prev_span).rfind('\n') {
219 Some(offset) => self.last_pos + BytePos(offset as u32),
220 None => source!(self, span).lo,
222 self.format_missing(span_end);
223 self.last_pos = source!(self, span).hi;
226 let s = format!("{}use {};", vis, s);
227 self.format_missing_with_indent(source!(self, span).lo);
228 self.buffer.push_str(&s);
229 self.last_pos = source!(self, span).hi;
232 self.format_missing_with_indent(source!(self, span).lo);
233 self.format_missing(source!(self, span).hi);
239 fn rewrite_single_use_list(path_str: Option<String>, vpi: &ast::PathListItem) -> String {
240 let path_item_str = match path_str {
241 Some(ref path_str) if vpi.node.name.to_string() == "self" => path_str.to_owned(),
242 Some(path_str) => format!("{}::{}", path_str, vpi.node.name),
243 None => vpi.node.name.to_string(),
246 append_alias(path_item_str, vpi)
249 fn rewrite_path_item(vpi: &&ast::PathListItem) -> Option<String> {
250 Some(append_alias(vpi.node.name.to_string(), vpi))
253 fn append_alias(path_item_str: String, vpi: &ast::PathListItem) -> String {
254 match vpi.node.rename {
255 Some(rename) => format!("{} as {}", path_item_str, rename),
256 None => path_item_str,
260 // Pretty prints a multi-item import.
261 // Assumes that path_list.len() > 0.
262 pub fn rewrite_use_list(width: usize,
265 path_list: &[ast::PathListItem],
267 context: &RewriteContext)
269 // Returns a different option to distinguish `::foo` and `foo`
270 let opt_path_str = if !path.to_string().is_empty() {
271 Some(path.to_string())
272 } else if path.global {
273 // path is absolute, we return an empty String to avoid a double `::`
279 match path_list.len() {
281 1 => return Some(rewrite_single_use_list(opt_path_str, &path_list[0])),
286 let path_separation_w = if opt_path_str.is_some() { 2 } else { 0 };
288 let supp_indent = path.to_string().len() + path_separation_w + 1;
290 let remaining_width = width.checked_sub(supp_indent + 1).unwrap_or(0);
293 // Dummy value, see explanation below.
294 let mut items = vec![ListItem::from_str("")];
295 let iter = itemize_list(context.codemap,
301 context.codemap.span_after(span, "{"),
307 // We prefixed the item list with a dummy value so that we can
308 // potentially move "self" to the front of the vector without touching
309 // the rest of the items.
310 let has_self = move_self_to_front(&mut items);
311 let first_index = if has_self { 0 } else { 1 };
313 if context.config.reorder_imported_names {
314 items[1..].sort_by(|a, b| a.item.cmp(&b.item));
317 let tactic = definitive_tactic(&items[first_index..],
318 ::lists::ListTactic::Mixed,
320 let fmt = ListFormatting {
323 trailing_separator: SeparatorTactic::Never,
324 indent: offset + supp_indent,
325 // FIXME This is too conservative, and will not use all width
327 // (loose 1 column (";"))
328 width: remaining_width,
329 ends_with_newline: false,
330 config: context.config,
332 let list_str = try_opt!(write_list(&items[first_index..], &fmt));
334 Some(match opt_path_str {
335 Some(opt_path_str) => format!("{}::{{{}}}", opt_path_str, list_str),
336 None => format!("{{{}}}", list_str),
340 // Returns true when self item was found.
341 fn move_self_to_front(items: &mut Vec<ListItem>) -> bool {
342 match items.iter().position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self")) {
344 items[0] = items.remove(pos);