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, PathContext};
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 {
35 .cmp(&b.identifier.name.as_str())
38 fn compare_paths(a: &ast::Path, b: &ast::Path) -> Ordering {
39 for segment in a.segments.iter().zip(b.segments.iter()) {
40 let ord = compare_path_segments(segment.0, segment.1);
41 if ord != Ordering::Equal {
45 a.segments.len().cmp(&b.segments.len())
48 fn compare_path_list_items(a: &ast::PathListItem, b: &ast::PathListItem) -> Ordering {
49 let a_name_str = &*a.node.name.name.as_str();
50 let b_name_str = &*b.node.name.name.as_str();
51 let name_ordering = if a_name_str == "self" {
52 if b_name_str == "self" {
58 if b_name_str == "self" {
61 a_name_str.cmp(&b_name_str)
64 if name_ordering == Ordering::Equal {
68 Some(b_rename) => a_rename.name.as_str().cmp(&b_rename.name.as_str()),
69 None => Ordering::Greater,
72 None => Ordering::Less,
79 fn compare_path_list_item_lists(a_items: &Vec<ast::PathListItem>,
80 b_items: &Vec<ast::PathListItem>)
82 let mut a = a_items.clone();
83 let mut b = b_items.clone();
84 a.sort_by(|a, b| compare_path_list_items(a, b));
85 b.sort_by(|a, b| compare_path_list_items(a, b));
86 for comparison_pair in a.iter().zip(b.iter()) {
87 let ord = compare_path_list_items(comparison_pair.0, comparison_pair.1);
88 if ord != Ordering::Equal {
95 fn compare_view_path_types(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering {
96 use syntax::ast::ViewPath_::*;
98 (&ViewPathSimple(..), &ViewPathSimple(..)) => Ordering::Equal,
99 (&ViewPathSimple(..), _) => Ordering::Less,
100 (&ViewPathGlob(_), &ViewPathSimple(..)) => Ordering::Greater,
101 (&ViewPathGlob(_), &ViewPathGlob(_)) => Ordering::Equal,
102 (&ViewPathGlob(_), &ViewPathList(..)) => Ordering::Less,
103 (&ViewPathList(_, ref a_items), &ViewPathList(_, ref b_items)) => {
104 compare_path_list_item_lists(a_items, b_items)
106 (&ViewPathList(..), _) => Ordering::Greater,
110 fn compare_view_paths(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering {
111 match compare_paths(path_of(a), path_of(b)) {
112 Ordering::Equal => compare_view_path_types(a, b),
117 fn compare_use_items(a: &ast::Item, b: &ast::Item) -> Option<Ordering> {
118 match (&a.node, &b.node) {
119 (&ast::ItemKind::Use(ref a_vp), &ast::ItemKind::Use(ref b_vp)) => {
120 Some(compare_view_paths(&a_vp.node, &b_vp.node))
126 // TODO (some day) remove unused imports, expand globs, compress many single
127 // imports into a list import.
129 fn rewrite_view_path_prefix(path: &ast::Path,
130 context: &RewriteContext,
133 let path_str = if path.segments.last().unwrap().identifier.to_string() == "self" &&
134 path.segments.len() > 1 {
135 let path = &ast::Path {
136 span: path.span.clone(),
137 segments: path.segments[..path.segments.len() - 1].to_owned(),
139 try_opt!(rewrite_path(context, PathContext::Import, None, path, shape))
141 try_opt!(rewrite_path(context, PathContext::Import, None, path, shape))
146 impl Rewrite for ast::ViewPath {
147 // Returns an empty string when the ViewPath is empty (like foo::bar::{})
148 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
150 ast::ViewPath_::ViewPathList(_, ref path_list) if path_list.is_empty() => {
153 ast::ViewPath_::ViewPathList(ref path, ref path_list) => {
154 rewrite_use_list(shape, path, path_list, self.span, context)
156 ast::ViewPath_::ViewPathGlob(ref path) => {
158 let prefix_shape = try_opt!(shape.sub_width(3));
159 let path_str = try_opt!(rewrite_view_path_prefix(path, context, prefix_shape));
160 Some(format!("{}::*", path_str))
162 ast::ViewPath_::ViewPathSimple(ident, ref path) => {
163 let ident_str = ident.to_string();
165 let prefix_shape = try_opt!(shape.sub_width(ident_str.len() + 4));
166 let path_str = try_opt!(rewrite_view_path_prefix(path, context, prefix_shape));
168 Some(if path.segments.last().unwrap().identifier == ident {
171 format!("{} as {}", path_str, ident_str)
178 impl<'a> FmtVisitor<'a> {
179 pub fn format_imports(&mut self, use_items: &[ptr::P<ast::Item>]) {
180 // Find the location immediately before the first use item in the run. This must not lie
181 // before the current `self.last_pos`
182 let pos_before_first_use_item = use_items
185 cmp::max(self.last_pos,
188 .map(|attr| attr.span.lo)
190 .unwrap_or(p_i.span.lo))
192 .unwrap_or(self.last_pos);
193 // Construct a list of pairs, each containing a `use` item and the start of span before
195 let mut last_pos_of_prev_use_item = pos_before_first_use_item;
196 let mut ordered_use_items = use_items
199 let new_item = (&*p_i, last_pos_of_prev_use_item);
200 last_pos_of_prev_use_item = p_i.span.hi;
203 .collect::<Vec<_>>();
204 let pos_after_last_use_item = last_pos_of_prev_use_item;
205 // Order the imports by view-path & other import path properties
206 ordered_use_items.sort_by(|a, b| compare_use_items(a.0, b.0).unwrap());
207 // First, output the span before the first import
208 let prev_span_str = self.snippet(codemap::mk_sp(self.last_pos, pos_before_first_use_item));
209 // Look for purely trailing space at the start of the prefix snippet before a linefeed, or
210 // a prefix that's entirely horizontal whitespace.
211 let prefix_span_start = match prev_span_str.find('\n') {
212 Some(offset) if prev_span_str[..offset].trim().is_empty() => {
213 self.last_pos + BytePos(offset as u32)
215 None if prev_span_str.trim().is_empty() => pos_before_first_use_item,
218 // Look for indent (the line part preceding the use is all whitespace) and excise that
220 let span_end = match prev_span_str.rfind('\n') {
221 Some(offset) if prev_span_str[offset..].trim().is_empty() => {
222 self.last_pos + BytePos(offset as u32)
224 _ => pos_before_first_use_item,
227 self.last_pos = prefix_span_start;
228 self.format_missing(span_end);
229 for ordered in ordered_use_items {
230 // Fake out the formatter by setting `self.last_pos` to the appropriate location before
231 // each item before visiting it.
232 self.last_pos = ordered.1;
233 self.visit_item(ordered.0);
235 self.last_pos = pos_after_last_use_item;
238 pub fn format_import(&mut self, vis: &ast::Visibility, vp: &ast::ViewPath, span: Span) {
239 let vis = utils::format_visibility(vis);
240 let mut offset = self.block_indent;
241 offset.alignment += vis.len() + "use ".len();
243 match vp.rewrite(&self.get_context(),
244 Shape::legacy(self.config.max_width - offset.width() - 1, offset)) {
245 Some(ref s) if s.is_empty() => {
246 // Format up to last newline
247 let prev_span = codemap::mk_sp(self.last_pos, source!(self, span).lo);
248 let span_end = match self.snippet(prev_span).rfind('\n') {
249 Some(offset) => self.last_pos + BytePos(offset as u32),
250 None => source!(self, span).lo,
252 self.format_missing(span_end);
253 self.last_pos = source!(self, span).hi;
256 let s = format!("{}use {};", vis, s);
257 self.format_missing_with_indent(source!(self, span).lo);
258 self.buffer.push_str(&s);
259 self.last_pos = source!(self, span).hi;
262 self.format_missing_with_indent(source!(self, span).lo);
263 self.format_missing(source!(self, span).hi);
269 fn rewrite_single_use_list(path_str: String, vpi: &ast::PathListItem) -> String {
270 let mut item_str = vpi.node.name.to_string();
271 if item_str == "self" {
272 item_str = "".to_owned();
274 let path_item_str = if path_str.is_empty() {
275 if item_str.is_empty() {
280 } else if item_str.is_empty() {
283 format!("{}::{}", path_str, item_str)
285 append_alias(path_item_str, vpi)
288 fn rewrite_path_item(vpi: &&ast::PathListItem) -> Option<String> {
289 Some(append_alias(vpi.node.name.to_string(), vpi))
292 fn append_alias(path_item_str: String, vpi: &ast::PathListItem) -> String {
293 match vpi.node.rename {
294 Some(rename) => format!("{} as {}", path_item_str, rename),
295 None => path_item_str,
299 // Pretty prints a multi-item import.
300 // Assumes that path_list.len() > 0.
301 pub fn rewrite_use_list(shape: Shape,
303 path_list: &[ast::PathListItem],
305 context: &RewriteContext)
307 // Returns a different option to distinguish `::foo` and `foo`
308 let path_str = try_opt!(rewrite_path(context, PathContext::Import, None, path, shape));
310 match path_list.len() {
312 1 => return Some(rewrite_single_use_list(path_str, &path_list[0])),
316 let colons_offset = if path_str.is_empty() { 0 } else { 2 };
319 let remaining_width = shape
321 .checked_sub(path_str.len() + 2 + colons_offset)
325 // Dummy value, see explanation below.
326 let mut items = vec![ListItem::from_str("")];
327 let iter = itemize_list(context.codemap,
333 context.codemap.span_after(span, "{"),
339 // We prefixed the item list with a dummy value so that we can
340 // potentially move "self" to the front of the vector without touching
341 // the rest of the items.
342 let has_self = move_self_to_front(&mut items);
343 let first_index = if has_self { 0 } else { 1 };
345 if context.config.reorder_imported_names {
346 items[1..].sort_by(|a, b| a.item.cmp(&b.item));
350 let tactic = definitive_tactic(&items[first_index..],
351 ::lists::ListTactic::Mixed,
354 let fmt = ListFormatting {
357 trailing_separator: SeparatorTactic::Never,
358 // Add one to the indent to account for "{"
359 shape: Shape::legacy(remaining_width,
360 shape.indent + path_str.len() + colons_offset + 1),
361 ends_with_newline: false,
362 config: context.config,
364 let list_str = try_opt!(write_list(&items[first_index..], &fmt));
366 Some(if path_str.is_empty() {
367 format!("{{{}}}", list_str)
369 format!("{}::{{{}}}", path_str, list_str)
373 // Returns true when self item was found.
374 fn move_self_to_front(items: &mut Vec<ListItem>) -> bool {
377 .position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self")) {
379 items[0] = items.remove(pos);