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
53 let b_name_str = &*b.node
57 let name_ordering = if a_name_str == "self" {
58 if b_name_str == "self" {
64 if b_name_str == "self" {
67 a_name_str.cmp(&b_name_str)
70 if name_ordering == Ordering::Equal {
74 Some(b_rename) => a_rename.name.as_str().cmp(&b_rename.name.as_str()),
75 None => Ordering::Greater,
78 None => Ordering::Less,
85 fn compare_path_list_item_lists(a_items: &Vec<ast::PathListItem>,
86 b_items: &Vec<ast::PathListItem>)
88 let mut a = a_items.clone();
89 let mut b = b_items.clone();
90 a.sort_by(|a, b| compare_path_list_items(a, b));
91 b.sort_by(|a, b| compare_path_list_items(a, b));
92 for comparison_pair in a.iter().zip(b.iter()) {
93 let ord = compare_path_list_items(comparison_pair.0, comparison_pair.1);
94 if ord != Ordering::Equal {
101 fn compare_view_path_types(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering {
102 use syntax::ast::ViewPath_::*;
104 (&ViewPathSimple(..), &ViewPathSimple(..)) => Ordering::Equal,
105 (&ViewPathSimple(..), _) => Ordering::Less,
106 (&ViewPathGlob(_), &ViewPathSimple(..)) => Ordering::Greater,
107 (&ViewPathGlob(_), &ViewPathGlob(_)) => Ordering::Equal,
108 (&ViewPathGlob(_), &ViewPathList(..)) => Ordering::Less,
109 (&ViewPathList(_, ref a_items), &ViewPathList(_, ref b_items)) => {
110 compare_path_list_item_lists(a_items, b_items)
112 (&ViewPathList(..), _) => Ordering::Greater,
116 fn compare_view_paths(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering {
117 match compare_paths(path_of(a), path_of(b)) {
118 Ordering::Equal => compare_view_path_types(a, b),
123 fn compare_use_items(a: &ast::Item, b: &ast::Item) -> Option<Ordering> {
124 match (&a.node, &b.node) {
125 (&ast::ItemKind::Use(ref a_vp), &ast::ItemKind::Use(ref b_vp)) => {
126 Some(compare_view_paths(&a_vp.node, &b_vp.node))
132 // TODO (some day) remove unused imports, expand globs, compress many single
133 // imports into a list import.
135 fn rewrite_view_path_prefix(path: &ast::Path,
136 context: &RewriteContext,
139 let path_str = if path.segments
143 .to_string() == "self" && path.segments.len() > 1 {
144 let path = &ast::Path {
145 span: path.span.clone(),
146 segments: path.segments[..path.segments.len() - 1].to_owned(),
148 try_opt!(rewrite_path(context, PathContext::Import, None, path, shape))
150 try_opt!(rewrite_path(context, PathContext::Import, None, path, shape))
155 impl Rewrite for ast::ViewPath {
156 // Returns an empty string when the ViewPath is empty (like foo::bar::{})
157 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
159 ast::ViewPath_::ViewPathList(_, ref path_list) if path_list.is_empty() => {
162 ast::ViewPath_::ViewPathList(ref path, ref path_list) => {
163 rewrite_use_list(shape, path, path_list, self.span, context)
165 ast::ViewPath_::ViewPathGlob(ref path) => {
167 let prefix_shape = try_opt!(shape.sub_width(3));
168 let path_str = try_opt!(rewrite_view_path_prefix(path, context, prefix_shape));
169 Some(format!("{}::*", path_str))
171 ast::ViewPath_::ViewPathSimple(ident, ref path) => {
172 let ident_str = ident.to_string();
174 let prefix_shape = try_opt!(shape.sub_width(ident_str.len() + 4));
175 let path_str = try_opt!(rewrite_view_path_prefix(path, context, prefix_shape));
177 Some(if path.segments
180 .identifier == ident {
183 format!("{} as {}", path_str, ident_str)
190 impl<'a> FmtVisitor<'a> {
191 pub fn format_imports(&mut self, use_items: &[ptr::P<ast::Item>]) {
192 // Find the location immediately before the first use item in the run. This must not lie
193 // before the current `self.last_pos`
194 let pos_before_first_use_item = use_items.first()
196 cmp::max(self.last_pos,
199 .map(|attr| attr.span.lo)
201 .unwrap_or(p_i.span.lo))
203 .unwrap_or(self.last_pos);
204 // Construct a list of pairs, each containing a `use` item and the start of span before
206 let mut last_pos_of_prev_use_item = pos_before_first_use_item;
207 let mut ordered_use_items = use_items.iter()
209 let new_item = (&*p_i, last_pos_of_prev_use_item);
210 last_pos_of_prev_use_item = p_i.span.hi;
213 .collect::<Vec<_>>();
214 let pos_after_last_use_item = last_pos_of_prev_use_item;
215 // Order the imports by view-path & other import path properties
216 ordered_use_items.sort_by(|a, b| compare_use_items(a.0, b.0).unwrap());
217 // First, output the span before the first import
218 let prev_span_str = self.snippet(codemap::mk_sp(self.last_pos, pos_before_first_use_item));
219 // Look for purely trailing space at the start of the prefix snippet before a linefeed, or
220 // a prefix that's entirely horizontal whitespace.
221 let prefix_span_start = match prev_span_str.find('\n') {
222 Some(offset) if prev_span_str[..offset].trim().is_empty() => {
223 self.last_pos + BytePos(offset as u32)
225 None if prev_span_str.trim().is_empty() => pos_before_first_use_item,
228 // Look for indent (the line part preceding the use is all whitespace) and excise that
230 let span_end = match prev_span_str.rfind('\n') {
231 Some(offset) if prev_span_str[offset..].trim().is_empty() => {
232 self.last_pos + BytePos(offset as u32)
234 _ => pos_before_first_use_item,
237 self.last_pos = prefix_span_start;
238 self.format_missing(span_end);
239 for ordered in ordered_use_items {
240 // Fake out the formatter by setting `self.last_pos` to the appropriate location before
241 // each item before visiting it.
242 self.last_pos = ordered.1;
243 self.visit_item(ordered.0);
245 self.last_pos = pos_after_last_use_item;
248 pub fn format_import(&mut self, vis: &ast::Visibility, vp: &ast::ViewPath, span: Span) {
249 let vis = utils::format_visibility(vis);
250 let mut offset = self.block_indent;
251 offset.alignment += vis.len() + "use ".len();
253 match vp.rewrite(&self.get_context(),
254 Shape::legacy(self.config.max_width - offset.width() - 1, offset)) {
255 Some(ref s) if s.is_empty() => {
256 // Format up to last newline
257 let prev_span = codemap::mk_sp(self.last_pos, source!(self, span).lo);
258 let span_end = match self.snippet(prev_span).rfind('\n') {
259 Some(offset) => self.last_pos + BytePos(offset as u32),
260 None => source!(self, span).lo,
262 self.format_missing(span_end);
263 self.last_pos = source!(self, span).hi;
266 let s = format!("{}use {};", vis, s);
267 self.format_missing_with_indent(source!(self, span).lo);
268 self.buffer.push_str(&s);
269 self.last_pos = source!(self, span).hi;
272 self.format_missing_with_indent(source!(self, span).lo);
273 self.format_missing(source!(self, span).hi);
279 fn rewrite_single_use_list(path_str: String, vpi: &ast::PathListItem) -> String {
280 let mut item_str = vpi.node.name.to_string();
281 if item_str == "self" {
282 item_str = "".to_owned();
284 let path_item_str = if path_str.is_empty() {
285 if item_str.is_empty() {
290 } else if item_str.is_empty() {
293 format!("{}::{}", path_str, item_str)
295 append_alias(path_item_str, vpi)
298 fn rewrite_path_item(vpi: &&ast::PathListItem) -> Option<String> {
299 Some(append_alias(vpi.node.name.to_string(), vpi))
302 fn append_alias(path_item_str: String, vpi: &ast::PathListItem) -> String {
303 match vpi.node.rename {
304 Some(rename) => format!("{} as {}", path_item_str, rename),
305 None => path_item_str,
309 // Pretty prints a multi-item import.
310 // Assumes that path_list.len() > 0.
311 pub fn rewrite_use_list(shape: Shape,
313 path_list: &[ast::PathListItem],
315 context: &RewriteContext)
317 // Returns a different option to distinguish `::foo` and `foo`
318 let path_str = try_opt!(rewrite_path(context, PathContext::Import, None, path, shape));
320 match path_list.len() {
322 1 => return Some(rewrite_single_use_list(path_str, &path_list[0])),
327 let remaining_width = shape.width.checked_sub(path_str.len() + 2).unwrap_or(0);
330 // Dummy value, see explanation below.
331 let mut items = vec![ListItem::from_str("")];
332 let iter = itemize_list(context.codemap,
338 context.codemap.span_after(span, "{"),
344 // We prefixed the item list with a dummy value so that we can
345 // potentially move "self" to the front of the vector without touching
346 // the rest of the items.
347 let has_self = move_self_to_front(&mut items);
348 let first_index = if has_self { 0 } else { 1 };
350 if context.config.reorder_imported_names {
351 items[1..].sort_by(|a, b| a.item.cmp(&b.item));
354 let colons_offset = if path_str.is_empty() { 0 } else { 2 };
356 let tactic = definitive_tactic(&items[first_index..],
357 ::lists::ListTactic::Mixed,
359 let fmt = ListFormatting {
362 trailing_separator: SeparatorTactic::Never,
363 // FIXME This is too conservative, and will not use all width
365 // (loose 1 column (";"))
366 shape: Shape::legacy(remaining_width,
367 shape.indent + path_str.len() + 1 + colons_offset),
368 ends_with_newline: false,
369 config: context.config,
371 let list_str = try_opt!(write_list(&items[first_index..], &fmt));
373 Some(if path_str.is_empty() {
374 format!("{{{}}}", list_str)
376 format!("{}::{{{}}}", path_str, list_str)
380 // Returns true when self item was found.
381 fn move_self_to_front(items: &mut Vec<ListItem>) -> bool {
382 match items.iter().position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self")) {
384 items[0] = items.remove(pos);