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 {
72 .cmp(&b_rename.name.as_str())
74 None => Ordering::Greater,
77 None => Ordering::Less,
84 fn compare_path_list_item_lists(a_items: &Vec<ast::PathListItem>,
85 b_items: &Vec<ast::PathListItem>)
87 let mut a = a_items.clone();
88 let mut b = b_items.clone();
89 a.sort_by(|a, b| compare_path_list_items(a, b));
90 b.sort_by(|a, b| compare_path_list_items(a, b));
91 for comparison_pair in a.iter().zip(b.iter()) {
92 let ord = compare_path_list_items(comparison_pair.0, comparison_pair.1);
93 if ord != Ordering::Equal {
100 fn compare_view_path_types(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering {
101 use syntax::ast::ViewPath_::*;
103 (&ViewPathSimple(..), &ViewPathSimple(..)) => Ordering::Equal,
104 (&ViewPathSimple(..), _) => Ordering::Less,
105 (&ViewPathGlob(_), &ViewPathSimple(..)) => Ordering::Greater,
106 (&ViewPathGlob(_), &ViewPathGlob(_)) => Ordering::Equal,
107 (&ViewPathGlob(_), &ViewPathList(..)) => Ordering::Less,
108 (&ViewPathList(_, ref a_items), &ViewPathList(_, ref b_items)) => {
109 compare_path_list_item_lists(a_items, b_items)
111 (&ViewPathList(..), _) => Ordering::Greater,
115 fn compare_view_paths(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering {
116 match compare_paths(path_of(a), path_of(b)) {
117 Ordering::Equal => compare_view_path_types(a, b),
122 fn compare_use_items(a: &ast::Item, b: &ast::Item) -> Option<Ordering> {
123 match (&a.node, &b.node) {
124 (&ast::ItemKind::Use(ref a_vp), &ast::ItemKind::Use(ref b_vp)) => {
125 Some(compare_view_paths(&a_vp.node, &b_vp.node))
131 // TODO (some day) remove unused imports, expand globs, compress many single
132 // imports into a list import.
134 fn rewrite_view_path_prefix(path: &ast::Path,
135 context: &RewriteContext,
138 let path_str = if path.segments
142 .to_string() == "self" && path.segments.len() > 1 {
143 let path = &ast::Path {
144 span: path.span.clone(),
145 segments: path.segments[..path.segments.len() - 1].to_owned(),
147 try_opt!(rewrite_path(context, PathContext::Import, None, path, shape))
149 try_opt!(rewrite_path(context, PathContext::Import, None, path, shape))
154 impl Rewrite for ast::ViewPath {
155 // Returns an empty string when the ViewPath is empty (like foo::bar::{})
156 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
158 ast::ViewPath_::ViewPathList(_, ref path_list) if path_list.is_empty() => {
161 ast::ViewPath_::ViewPathList(ref path, ref path_list) => {
162 rewrite_use_list(shape, path, path_list, self.span, context)
164 ast::ViewPath_::ViewPathGlob(ref path) => {
166 let prefix_shape = try_opt!(shape.sub_width(3));
167 let path_str = try_opt!(rewrite_view_path_prefix(path, context, prefix_shape));
168 Some(format!("{}::*", path_str))
170 ast::ViewPath_::ViewPathSimple(ident, ref path) => {
171 let ident_str = ident.to_string();
173 let prefix_shape = try_opt!(shape.sub_width(ident_str.len() + 4));
174 let path_str = try_opt!(rewrite_view_path_prefix(path, context, prefix_shape));
176 Some(if path.segments.last().unwrap().identifier == ident {
179 format!("{} as {}", path_str, ident_str)
186 impl<'a> FmtVisitor<'a> {
187 pub fn format_imports(&mut self, use_items: &[ptr::P<ast::Item>]) {
188 // Find the location immediately before the first use item in the run. This must not lie
189 // before the current `self.last_pos`
190 let pos_before_first_use_item = use_items
193 cmp::max(self.last_pos,
196 .map(|attr| attr.span.lo)
198 .unwrap_or(p_i.span.lo))
200 .unwrap_or(self.last_pos);
201 // Construct a list of pairs, each containing a `use` item and the start of span before
203 let mut last_pos_of_prev_use_item = pos_before_first_use_item;
204 let mut ordered_use_items = use_items
207 let new_item = (&*p_i, last_pos_of_prev_use_item);
208 last_pos_of_prev_use_item = p_i.span.hi;
211 .collect::<Vec<_>>();
212 let pos_after_last_use_item = last_pos_of_prev_use_item;
213 // Order the imports by view-path & other import path properties
214 ordered_use_items.sort_by(|a, b| compare_use_items(a.0, b.0).unwrap());
215 // First, output the span before the first import
216 let prev_span_str = self.snippet(codemap::mk_sp(self.last_pos, pos_before_first_use_item));
217 // Look for purely trailing space at the start of the prefix snippet before a linefeed, or
218 // a prefix that's entirely horizontal whitespace.
219 let prefix_span_start = match prev_span_str.find('\n') {
220 Some(offset) if prev_span_str[..offset].trim().is_empty() => {
221 self.last_pos + BytePos(offset as u32)
223 None if prev_span_str.trim().is_empty() => pos_before_first_use_item,
226 // Look for indent (the line part preceding the use is all whitespace) and excise that
228 let span_end = match prev_span_str.rfind('\n') {
229 Some(offset) if prev_span_str[offset..].trim().is_empty() => {
230 self.last_pos + BytePos(offset as u32)
232 _ => pos_before_first_use_item,
235 self.last_pos = prefix_span_start;
236 self.format_missing(span_end);
237 for ordered in ordered_use_items {
238 // Fake out the formatter by setting `self.last_pos` to the appropriate location before
239 // each item before visiting it.
240 self.last_pos = ordered.1;
241 self.visit_item(ordered.0);
243 self.last_pos = pos_after_last_use_item;
246 pub fn format_import(&mut self, vis: &ast::Visibility, vp: &ast::ViewPath, span: Span) {
247 let vis = utils::format_visibility(vis);
248 let mut offset = self.block_indent;
249 offset.alignment += vis.len() + "use ".len();
251 match vp.rewrite(&self.get_context(),
252 Shape::legacy(self.config.max_width - offset.width() - 1, offset)) {
253 Some(ref s) if s.is_empty() => {
254 // Format up to last newline
255 let prev_span = codemap::mk_sp(self.last_pos, source!(self, span).lo);
256 let span_end = match self.snippet(prev_span).rfind('\n') {
257 Some(offset) => self.last_pos + BytePos(offset as u32),
258 None => source!(self, span).lo,
260 self.format_missing(span_end);
261 self.last_pos = source!(self, span).hi;
264 let s = format!("{}use {};", vis, s);
265 self.format_missing_with_indent(source!(self, span).lo);
266 self.buffer.push_str(&s);
267 self.last_pos = source!(self, span).hi;
270 self.format_missing_with_indent(source!(self, span).lo);
271 self.format_missing(source!(self, span).hi);
277 fn rewrite_single_use_list(path_str: String, vpi: &ast::PathListItem) -> String {
278 let mut item_str = vpi.node.name.to_string();
279 if item_str == "self" {
280 item_str = "".to_owned();
282 let path_item_str = if path_str.is_empty() {
283 if item_str.is_empty() {
288 } else if item_str.is_empty() {
291 format!("{}::{}", path_str, item_str)
293 append_alias(path_item_str, vpi)
296 fn rewrite_path_item(vpi: &&ast::PathListItem) -> Option<String> {
297 Some(append_alias(vpi.node.name.to_string(), vpi))
300 fn append_alias(path_item_str: String, vpi: &ast::PathListItem) -> String {
301 match vpi.node.rename {
302 Some(rename) => format!("{} as {}", path_item_str, rename),
303 None => path_item_str,
307 // Pretty prints a multi-item import.
308 // Assumes that path_list.len() > 0.
309 pub fn rewrite_use_list(shape: Shape,
311 path_list: &[ast::PathListItem],
313 context: &RewriteContext)
315 // Returns a different option to distinguish `::foo` and `foo`
316 let path_str = try_opt!(rewrite_path(context, PathContext::Import, None, path, shape));
318 match path_list.len() {
320 1 => return Some(rewrite_single_use_list(path_str, &path_list[0])),
324 let colons_offset = if path_str.is_empty() { 0 } else { 2 };
327 let remaining_width = shape
329 .checked_sub(path_str.len() + 2 + colons_offset)
333 // Dummy value, see explanation below.
334 let mut items = vec![ListItem::from_str("")];
335 let iter = itemize_list(context.codemap,
341 context.codemap.span_after(span, "{"),
347 // We prefixed the item list with a dummy value so that we can
348 // potentially move "self" to the front of the vector without touching
349 // the rest of the items.
350 let has_self = move_self_to_front(&mut items);
351 let first_index = if has_self { 0 } else { 1 };
353 if context.config.reorder_imported_names {
354 items[1..].sort_by(|a, b| a.item.cmp(&b.item));
358 let tactic = definitive_tactic(&items[first_index..],
359 ::lists::ListTactic::Mixed,
362 let fmt = ListFormatting {
365 trailing_separator: SeparatorTactic::Never,
366 // Add one to the indent to account for "{"
367 shape: Shape::legacy(remaining_width,
368 shape.indent + path_str.len() + colons_offset + 1),
369 ends_with_newline: false,
370 config: context.config,
372 let list_str = try_opt!(write_list(&items[first_index..], &fmt));
374 Some(if path_str.is_empty() {
375 format!("{{{}}}", list_str)
377 format!("{}::{{{}}}", path_str, list_str)
381 // Returns true when self item was found.
382 fn move_self_to_front(items: &mut Vec<ListItem>) -> bool {
385 .position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self")) {
387 items[0] = items.remove(pos);