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.
11 use std::cmp::{self, Ordering};
13 use syntax::{ast, ptr};
14 use syntax::codemap::{BytePos, Span};
17 use codemap::SpanUtils;
18 use lists::{definitive_tactic, itemize_list, write_list, ListFormatting, ListItem, SeparatorTactic};
19 use rewrite::{Rewrite, RewriteContext};
20 use types::{rewrite_path, PathContext};
22 use visitor::FmtVisitor;
24 fn path_of(a: &ast::ViewPath_) -> &ast::Path {
26 ast::ViewPath_::ViewPathSimple(_, ref p) => p,
27 ast::ViewPath_::ViewPathGlob(ref p) => p,
28 ast::ViewPath_::ViewPathList(ref p, _) => p,
32 fn compare_path_segments(a: &ast::PathSegment, b: &ast::PathSegment) -> Ordering {
33 a.identifier.name.as_str().cmp(&b.identifier.name.as_str())
36 fn compare_paths(a: &ast::Path, b: &ast::Path) -> Ordering {
37 for segment in a.segments.iter().zip(b.segments.iter()) {
38 let ord = compare_path_segments(segment.0, segment.1);
39 if ord != Ordering::Equal {
43 a.segments.len().cmp(&b.segments.len())
46 fn compare_path_list_items(a: &ast::PathListItem, b: &ast::PathListItem) -> Ordering {
47 let a_name_str = &*a.node.name.name.as_str();
48 let b_name_str = &*b.node.name.name.as_str();
49 let name_ordering = if a_name_str == "self" {
50 if b_name_str == "self" {
56 if b_name_str == "self" {
59 a_name_str.cmp(&b_name_str)
62 if name_ordering == Ordering::Equal {
64 Some(a_rename) => match b.node.rename {
65 Some(b_rename) => a_rename.name.as_str().cmp(&b_rename.name.as_str()),
66 None => Ordering::Greater,
68 None => Ordering::Less,
75 fn compare_path_list_item_lists(
76 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 fn rewrite_view_path_prefix(
128 context: &RewriteContext,
130 ) -> Option<String> {
131 let path_str = if path.segments.last().unwrap().identifier.to_string() == "self" &&
132 path.segments.len() > 1
134 let path = &ast::Path {
135 span: path.span.clone(),
136 segments: path.segments[..path.segments.len() - 1].to_owned(),
138 try_opt!(rewrite_path(
146 try_opt!(rewrite_path(
157 impl Rewrite for ast::ViewPath {
158 // Returns an empty string when the ViewPath is empty (like foo::bar::{})
159 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
161 ast::ViewPath_::ViewPathList(_, ref path_list) if path_list.is_empty() => {
164 ast::ViewPath_::ViewPathList(ref path, ref path_list) => {
165 rewrite_use_list(shape, path, path_list, self.span, context)
167 ast::ViewPath_::ViewPathGlob(ref path) => {
169 let prefix_shape = try_opt!(shape.sub_width(3));
170 let path_str = try_opt!(rewrite_view_path_prefix(path, context, prefix_shape));
171 Some(format!("{}::*", path_str))
173 ast::ViewPath_::ViewPathSimple(ident, ref path) => {
174 let ident_str = ident.to_string();
176 let prefix_shape = try_opt!(shape.sub_width(ident_str.len() + 4));
177 let path_str = try_opt!(rewrite_view_path_prefix(path, context, prefix_shape));
179 Some(if path.segments.last().unwrap().identifier == ident {
182 format!("{} as {}", path_str, ident_str)
189 impl<'a> FmtVisitor<'a> {
190 pub fn format_imports(&mut self, use_items: &[ptr::P<ast::Item>]) {
191 // Find the location immediately before the first use item in the run. This must not lie
192 // before the current `self.last_pos`
193 let pos_before_first_use_item = use_items
200 .map(|attr| attr.span.lo)
202 .unwrap_or(p_i.span.lo),
205 .unwrap_or(self.last_pos);
206 // Construct a list of pairs, each containing a `use` item and the start of span before
208 let mut last_pos_of_prev_use_item = pos_before_first_use_item;
209 let mut ordered_use_items = use_items
212 let new_item = (&*p_i, last_pos_of_prev_use_item);
213 last_pos_of_prev_use_item = p_i.span.hi;
216 .collect::<Vec<_>>();
217 let pos_after_last_use_item = last_pos_of_prev_use_item;
218 // Order the imports by view-path & other import path properties
219 ordered_use_items.sort_by(|a, b| compare_use_items(a.0, b.0).unwrap());
220 // First, output the span before the first import
221 let prev_span_str = self.snippet(utils::mk_sp(self.last_pos, pos_before_first_use_item));
222 // Look for purely trailing space at the start of the prefix snippet before a linefeed, or
223 // a prefix that's entirely horizontal whitespace.
224 let prefix_span_start = match prev_span_str.find('\n') {
225 Some(offset) if prev_span_str[..offset].trim().is_empty() => {
226 self.last_pos + BytePos(offset as u32)
228 None if prev_span_str.trim().is_empty() => pos_before_first_use_item,
231 // Look for indent (the line part preceding the use is all whitespace) and excise that
233 let span_end = match prev_span_str.rfind('\n') {
234 Some(offset) if prev_span_str[offset..].trim().is_empty() => {
235 self.last_pos + BytePos(offset as u32)
237 _ => pos_before_first_use_item,
240 self.last_pos = prefix_span_start;
241 self.format_missing(span_end);
242 for ordered in ordered_use_items {
243 // Fake out the formatter by setting `self.last_pos` to the appropriate location before
244 // each item before visiting it.
245 self.last_pos = ordered.1;
246 self.visit_item(ordered.0);
248 self.last_pos = pos_after_last_use_item;
251 pub fn format_import(&mut self, vis: &ast::Visibility, vp: &ast::ViewPath, span: Span) {
252 let vis = utils::format_visibility(vis);
253 let mut offset = self.block_indent;
254 offset.alignment += vis.len() + "use ".len();
258 Shape::legacy(self.config.max_width() - offset.width() - 1, offset),
260 Some(ref s) if s.is_empty() => {
261 // Format up to last newline
262 let prev_span = utils::mk_sp(self.last_pos, source!(self, span).lo);
263 let span_end = match self.snippet(prev_span).rfind('\n') {
264 Some(offset) => self.last_pos + BytePos(offset as u32),
265 None => source!(self, span).lo,
267 self.format_missing(span_end);
268 self.last_pos = source!(self, span).hi;
271 let s = format!("{}use {};", vis, s);
272 self.format_missing_with_indent(source!(self, span).lo);
273 self.buffer.push_str(&s);
274 self.last_pos = source!(self, span).hi;
277 self.format_missing_with_indent(source!(self, span).lo);
278 self.format_missing(source!(self, span).hi);
284 fn rewrite_single_use_list(path_str: String, vpi: &ast::PathListItem) -> String {
285 let mut item_str = vpi.node.name.to_string();
286 if item_str == "self" {
287 item_str = "".to_owned();
289 let path_item_str = if path_str.is_empty() {
290 if item_str.is_empty() {
295 } else if item_str.is_empty() {
298 format!("{}::{}", path_str, item_str)
300 append_alias(path_item_str, vpi)
303 fn rewrite_path_item(vpi: &&ast::PathListItem) -> Option<String> {
304 Some(append_alias(vpi.node.name.to_string(), vpi))
307 fn append_alias(path_item_str: String, vpi: &ast::PathListItem) -> String {
308 match vpi.node.rename {
309 Some(rename) => format!("{} as {}", path_item_str, rename),
310 None => path_item_str,
314 #[derive(Eq, PartialEq)]
315 enum ImportItem<'a> {
316 // `self` or `self as a`
318 // name_one, name_two, ...
320 // NameOne, NameTwo, ...
322 // NAME_ONE, NAME_TWO, ...
324 // Failed to format the import item
328 impl<'a> ImportItem<'a> {
329 fn from_str(s: &str) -> ImportItem {
330 if s == "self" || s.starts_with("self as") {
331 ImportItem::SelfImport(s)
332 } else if s.chars().all(|c| c.is_lowercase() || c == '_' || c == ' ') {
333 ImportItem::SnakeCase(s)
334 } else if s.chars().all(|c| c.is_uppercase() || c == '_' || c == ' ') {
335 ImportItem::AllCaps(s)
337 ImportItem::CamelCase(s)
341 fn from_opt_str(s: Option<&String>) -> ImportItem {
342 s.map_or(ImportItem::Invalid, |s| ImportItem::from_str(s))
345 fn to_str(&self) -> Option<&str> {
347 ImportItem::SelfImport(s) |
348 ImportItem::SnakeCase(s) |
349 ImportItem::CamelCase(s) |
350 ImportItem::AllCaps(s) => Some(s),
351 ImportItem::Invalid => None,
355 fn to_u32(&self) -> u32 {
357 ImportItem::SelfImport(..) => 0,
358 ImportItem::SnakeCase(..) => 1,
359 ImportItem::CamelCase(..) => 2,
360 ImportItem::AllCaps(..) => 3,
361 ImportItem::Invalid => 4,
366 impl<'a> PartialOrd for ImportItem<'a> {
367 fn partial_cmp(&self, other: &ImportItem<'a>) -> Option<Ordering> {
368 Some(self.cmp(other))
372 impl<'a> Ord for ImportItem<'a> {
373 fn cmp(&self, other: &ImportItem<'a>) -> Ordering {
374 let res = self.to_u32().cmp(&other.to_u32());
375 if res != Ordering::Equal {
378 self.to_str().map_or(Ordering::Greater, |self_str| {
381 .map_or(Ordering::Less, |other_str| self_str.cmp(other_str))
386 // Pretty prints a multi-item import.
387 // Assumes that path_list.len() > 0.
388 pub fn rewrite_use_list(
391 path_list: &[ast::PathListItem],
393 context: &RewriteContext,
394 ) -> Option<String> {
395 // Returns a different option to distinguish `::foo` and `foo`
396 let path_str = try_opt!(rewrite_path(
404 match path_list.len() {
406 1 => return Some(rewrite_single_use_list(path_str, &path_list[0])),
410 let colons_offset = if path_str.is_empty() { 0 } else { 2 };
413 let remaining_width = shape
415 .checked_sub(path_str.len() + 2 + colons_offset)
419 // Dummy value, see explanation below.
420 let mut items = vec![ListItem::from_str("")];
421 let iter = itemize_list(
428 context.codemap.span_after(span, "{"),
435 // We prefixed the item list with a dummy value so that we can
436 // potentially move "self" to the front of the vector without touching
437 // the rest of the items.
438 let has_self = move_self_to_front(&mut items);
439 let first_index = if has_self { 0 } else { 1 };
441 if context.config.reorder_imported_names() {
442 items[1..].sort_by(|a, b| {
443 let a = ImportItem::from_opt_str(a.item.as_ref());
444 let b = ImportItem::from_opt_str(b.item.as_ref());
450 let tactic = definitive_tactic(
451 &items[first_index..],
452 ::lists::ListTactic::Mixed,
456 let fmt = ListFormatting {
459 trailing_separator: SeparatorTactic::Never,
460 // Add one to the indent to account for "{"
461 shape: Shape::legacy(
463 shape.indent + path_str.len() + colons_offset + 1,
465 ends_with_newline: false,
466 config: context.config,
468 let list_str = try_opt!(write_list(&items[first_index..], &fmt));
470 Some(if path_str.is_empty() {
471 format!("{{{}}}", list_str)
473 format!("{}::{{{}}}", path_str, list_str)
477 // Returns true when self item was found.
478 fn move_self_to_front(items: &mut Vec<ListItem>) -> bool {
481 .position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self")) {
483 items[0] = items.remove(pos);