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::Ordering;
14 use syntax::codemap::{BytePos, Span};
16 use codemap::SpanUtils;
17 use comment::combine_strs_with_missing_comments;
18 use config::IndentStyle;
19 use lists::{definitive_tactic, itemize_list, write_list, DefinitiveListTactic, ListFormatting,
20 ListItem, Separator, SeparatorPlace, SeparatorTactic};
21 use rewrite::{Rewrite, RewriteContext};
24 use types::{rewrite_path, PathContext};
25 use utils::{format_visibility, mk_sp};
26 use visitor::{rewrite_extern_crate, FmtVisitor};
28 fn compare_path_segments(a: &ast::PathSegment, b: &ast::PathSegment) -> Ordering {
29 a.identifier.name.as_str().cmp(&b.identifier.name.as_str())
32 fn compare_paths(a: &ast::Path, b: &ast::Path) -> Ordering {
33 for segment in a.segments.iter().zip(b.segments.iter()) {
34 let ord = compare_path_segments(segment.0, segment.1);
35 if ord != Ordering::Equal {
39 a.segments.len().cmp(&b.segments.len())
42 fn compare_use_trees(a: &ast::UseTree, b: &ast::UseTree, nested: bool) -> Ordering {
43 use ast::UseTreeKind::*;
45 // `use_nested_groups` is not yet supported, remove the `if !nested` when support will be
48 let paths_cmp = compare_paths(&a.prefix, &b.prefix);
49 if paths_cmp != Ordering::Equal {
54 match (&a.kind, &b.kind) {
55 (&Simple(ident_a), &Simple(ident_b)) => {
56 let name_a = &*path_to_imported_ident(&a.prefix).name.as_str();
57 let name_b = &*path_to_imported_ident(&b.prefix).name.as_str();
58 let name_ordering = if name_a == "self" {
64 } else if name_b == "self" {
69 if name_ordering == Ordering::Equal {
70 if ident_a.name.as_str() != name_a {
71 if ident_b.name.as_str() != name_b {
72 ident_a.name.as_str().cmp(&ident_b.name.as_str())
83 (&Glob, &Glob) => Ordering::Equal,
84 (&Simple(_), _) | (&Glob, &Nested(_)) => Ordering::Less,
85 (&Nested(ref a_items), &Nested(ref b_items)) => {
88 .map(|&(ref tree, _)| tree.clone())
92 .map(|&(ref tree, _)| tree.clone())
94 a.sort_by(|a, b| compare_use_trees(a, b, true));
95 b.sort_by(|a, b| compare_use_trees(a, b, true));
96 for comparison_pair in a.iter().zip(b.iter()) {
97 let ord = compare_use_trees(comparison_pair.0, comparison_pair.1, true);
98 if ord != Ordering::Equal {
102 a.len().cmp(&b.len())
104 (&Glob, &Simple(_)) | (&Nested(_), _) => Ordering::Greater,
108 fn compare_use_items(a: &ast::Item, b: &ast::Item) -> Ordering {
109 match (&a.node, &b.node) {
110 (&ast::ItemKind::Mod(..), &ast::ItemKind::Mod(..)) => {
111 a.ident.name.as_str().cmp(&b.ident.name.as_str())
113 (&ast::ItemKind::Use(ref a_tree), &ast::ItemKind::Use(ref b_tree)) => {
114 compare_use_trees(a_tree, b_tree, false)
116 (&ast::ItemKind::ExternCrate(ref a_name), &ast::ItemKind::ExternCrate(ref b_name)) => {
117 // `extern crate foo as bar;`
118 // ^^^ Comparing this.
120 a_name.map_or_else(|| a.ident.name.as_str(), |symbol| symbol.as_str());
122 b_name.map_or_else(|| b.ident.name.as_str(), |symbol| symbol.as_str());
123 let result = a_orig_name.cmp(&b_orig_name);
124 if result != Ordering::Equal {
128 // `extern crate foo as bar;`
129 // ^^^ Comparing this.
130 let result = match (a_name, b_name) {
131 (Some(..), None) => Ordering::Greater,
132 (None, Some(..)) => Ordering::Less,
133 (None, None) => Ordering::Equal,
134 (Some(..), Some(..)) => a.ident.name.as_str().cmp(&b.ident.name.as_str()),
142 // TODO (some day) remove unused imports, expand globs, compress many single
143 // imports into a list import.
145 fn rewrite_prefix(path: &ast::Path, context: &RewriteContext, shape: Shape) -> Option<String> {
146 if path.segments.len() > 1 && path_to_imported_ident(path).to_string() == "self" {
147 let path = &ast::Path {
149 segments: path.segments[..path.segments.len() - 1].to_owned(),
151 rewrite_path(context, PathContext::Import, None, path, shape)
153 rewrite_path(context, PathContext::Import, None, path, shape)
157 impl Rewrite for ast::UseTree {
158 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
160 ast::UseTreeKind::Nested(ref items) => {
161 rewrite_nested_use_tree(shape, &self.prefix, items, self.span, context)
163 ast::UseTreeKind::Glob => {
164 let prefix_shape = shape.sub_width(3)?;
166 if !self.prefix.segments.is_empty() {
167 let path_str = rewrite_prefix(&self.prefix, context, prefix_shape)?;
168 Some(format!("{}::*", path_str))
173 ast::UseTreeKind::Simple(ident) => {
174 let ident_str = ident.to_string();
177 let is_same_name_bind = path_to_imported_ident(&self.prefix) == ident;
178 let prefix_shape = if is_same_name_bind {
181 shape.sub_width(ident_str.len() + 4)?
183 let path_str = rewrite_prefix(&self.prefix, context, prefix_shape)
184 .unwrap_or_else(|| context.snippet(self.prefix.span).to_owned());
186 if is_same_name_bind {
189 Some(format!("{} as {}", path_str, ident_str))
196 fn is_unused_import(tree: &ast::UseTree, attrs: &[ast::Attribute]) -> bool {
197 attrs.is_empty() && is_unused_import_inner(tree)
200 fn is_unused_import_inner(tree: &ast::UseTree) -> bool {
202 ast::UseTreeKind::Nested(ref items) => match items.len() {
204 1 => is_unused_import_inner(&items[0].0),
211 // Rewrite `use foo;` WITHOUT attributes.
213 context: &RewriteContext,
214 vis: &ast::Visibility,
216 attrs: &[ast::Attribute],
218 ) -> Option<String> {
219 let vis = format_visibility(vis);
220 // 4 = `use `, 1 = `;`
222 .offset_left(vis.len() + 4)
223 .and_then(|shape| shape.sub_width(1))
225 // If we have an empty nested group with no attributes, we erase it
226 if is_unused_import(tree, attrs) {
229 tree.rewrite(context, shape)
233 Some(ref s) if !s.is_empty() => Some(format!("{}use {};", vis, s)),
238 /// Rewrite an inline mod.
239 fn rewrite_mod(item: &ast::Item) -> String {
240 let mut result = String::with_capacity(32);
241 result.push_str(&*format_visibility(&item.vis));
242 result.push_str("mod ");
243 result.push_str(&item.ident.to_string());
249 context: &RewriteContext,
250 use_items: &[&ast::Item],
253 ) -> Option<String> {
254 let items = itemize_list(
259 |item| item.span().lo(),
260 |item| item.span().hi(),
262 let attrs = ::visitor::filter_inline_attrs(&item.attrs, item.span());
263 let attrs_str = attrs.rewrite(context, shape)?;
265 let missed_span = if attrs.is_empty() {
266 mk_sp(item.span.lo(), item.span.lo())
268 mk_sp(attrs.last().unwrap().span.hi(), item.span.lo())
271 let item_str = match item.node {
272 ast::ItemKind::Use(ref tree) => {
273 rewrite_import(context, &item.vis, tree, &item.attrs, shape)?
275 ast::ItemKind::ExternCrate(..) => rewrite_extern_crate(context, item)?,
276 ast::ItemKind::Mod(..) => rewrite_mod(item),
280 combine_strs_with_missing_comments(
293 let mut item_pair_vec: Vec<_> = items.zip(use_items.iter()).collect();
294 item_pair_vec.sort_by(|a, b| compare_use_items(a.1, b.1));
295 let item_vec: Vec<_> = item_pair_vec.into_iter().map(|pair| pair.0).collect();
297 let fmt = ListFormatting {
298 tactic: DefinitiveListTactic::Vertical,
300 trailing_separator: SeparatorTactic::Never,
301 separator_place: SeparatorPlace::Back,
303 ends_with_newline: true,
304 preserve_newline: false,
305 config: context.config,
308 write_list(&item_vec, &fmt)
311 impl<'a> FmtVisitor<'a> {
312 pub fn format_imports(&mut self, use_items: &[&ast::Item]) {
313 if use_items.is_empty() {
317 let lo = use_items.first().unwrap().span().lo();
318 let hi = use_items.last().unwrap().span().hi();
319 let span = mk_sp(lo, hi);
320 let rw = rewrite_imports(&self.get_context(), use_items, self.shape(), span);
321 self.push_rewrite(span, rw);
324 pub fn format_import(&mut self, item: &ast::Item, tree: &ast::UseTree) {
325 let span = item.span;
326 let shape = self.shape();
327 let rw = rewrite_import(&self.get_context(), &item.vis, tree, &item.attrs, shape);
329 Some(ref s) if s.is_empty() => {
330 // Format up to last newline
331 let prev_span = mk_sp(self.last_pos, source!(self, span).lo());
332 let trimmed_snippet = self.snippet(prev_span).trim_right();
333 let span_end = self.last_pos + BytePos(trimmed_snippet.len() as u32);
334 self.format_missing(span_end);
335 // We have an excessive newline from the removed import.
336 if self.buffer.ends_with('\n') {
338 self.line_number -= 1;
340 self.last_pos = source!(self, span).hi();
343 self.format_missing_with_indent(source!(self, span).lo());
345 self.last_pos = source!(self, span).hi();
348 self.format_missing_with_indent(source!(self, span).lo());
349 self.format_missing(source!(self, span).hi());
355 fn rewrite_nested_use_tree_single(
356 context: &RewriteContext,
360 ) -> Option<String> {
362 ast::UseTreeKind::Simple(rename) => {
363 let ident = path_to_imported_ident(&tree.prefix);
364 let mut item_str = rewrite_prefix(&tree.prefix, context, shape)?;
365 if item_str == "self" {
366 item_str = "".to_owned();
369 let path_item_str = if path_str.is_empty() {
370 if item_str.is_empty() {
375 } else if item_str.is_empty() {
378 format!("{}::{}", path_str, item_str)
381 Some(if ident == rename {
384 format!("{} as {}", path_item_str, rename)
387 ast::UseTreeKind::Glob | ast::UseTreeKind::Nested(..) => {
389 let nested_shape = shape.offset_left(path_str.len() + 2)?;
390 tree.rewrite(context, nested_shape)
391 .map(|item| format!("{}::{}", path_str, item))
396 #[derive(Eq, PartialEq)]
397 enum ImportItem<'a> {
398 // `self` or `self as a`
400 // name_one, name_two, ...
402 // NameOne, NameTwo, ...
404 // NAME_ONE, NAME_TWO, ...
406 // Failed to format the import item
410 impl<'a> ImportItem<'a> {
411 fn from_str(s: &str) -> ImportItem {
412 if s == "self" || s.starts_with("self as") {
413 ImportItem::SelfImport(s)
414 } else if s.chars().all(|c| c.is_lowercase() || c == '_' || c == ' ') {
415 ImportItem::SnakeCase(s)
416 } else if s.chars().all(|c| c.is_uppercase() || c == '_' || c == ' ') {
417 ImportItem::AllCaps(s)
419 ImportItem::CamelCase(s)
423 fn from_opt_str(s: Option<&String>) -> ImportItem {
424 s.map_or(ImportItem::Invalid, |s| ImportItem::from_str(s))
427 fn to_str(&self) -> Option<&str> {
429 ImportItem::SelfImport(s)
430 | ImportItem::SnakeCase(s)
431 | ImportItem::CamelCase(s)
432 | ImportItem::AllCaps(s) => Some(s),
433 ImportItem::Invalid => None,
437 fn to_u32(&self) -> u32 {
439 ImportItem::SelfImport(..) => 0,
440 ImportItem::SnakeCase(..) => 1,
441 ImportItem::CamelCase(..) => 2,
442 ImportItem::AllCaps(..) => 3,
443 ImportItem::Invalid => 4,
448 impl<'a> PartialOrd for ImportItem<'a> {
449 fn partial_cmp(&self, other: &ImportItem<'a>) -> Option<Ordering> {
450 Some(self.cmp(other))
454 impl<'a> Ord for ImportItem<'a> {
455 fn cmp(&self, other: &ImportItem<'a>) -> Ordering {
456 let res = self.to_u32().cmp(&other.to_u32());
457 if res != Ordering::Equal {
460 self.to_str().map_or(Ordering::Greater, |self_str| {
463 .map_or(Ordering::Less, |other_str| self_str.cmp(other_str))
468 // Pretty prints a multi-item import.
469 // If the path list is empty, it leaves the braces empty.
470 fn rewrite_nested_use_tree(
473 trees: &[(ast::UseTree, ast::NodeId)],
475 context: &RewriteContext,
476 ) -> Option<String> {
477 // Returns a different option to distinguish `::foo` and `foo`
478 let path_str = rewrite_path(context, PathContext::Import, None, path, shape)?;
482 let shape = shape.offset_left(path_str.len() + 3)?;
483 return rewrite_path(context, PathContext::Import, None, path, shape)
484 .map(|path_str| format!("{}::{{}}", path_str));
487 return rewrite_nested_use_tree_single(context, &path_str, &trees[0].0, shape);
492 let path_str = if path_str.is_empty() {
495 format!("{}::", path_str)
499 let remaining_width = shape.width.checked_sub(path_str.len() + 2).unwrap_or(0);
500 let nested_indent = match context.config.imports_indent() {
501 IndentStyle::Block => shape.indent.block_indent(context.config),
503 IndentStyle::Visual => shape.visual_indent(path_str.len() + 1).indent,
506 let nested_shape = match context.config.imports_indent() {
507 IndentStyle::Block => Shape::indented(nested_indent, context.config).sub_width(1)?,
508 IndentStyle::Visual => Shape::legacy(remaining_width, nested_indent),
512 // Dummy value, see explanation below.
513 let mut items = vec![ListItem::from_str("")];
514 let iter = itemize_list(
516 trees.iter().map(|tree| &tree.0),
519 |tree| tree.span.lo(),
520 |tree| tree.span.hi(),
521 |tree| tree.rewrite(context, nested_shape),
522 context.codemap.span_after(span, "{"),
530 // We prefixed the item list with a dummy value so that we can
531 // potentially move "self" to the front of the vector without touching
532 // the rest of the items.
533 let has_self = move_self_to_front(&mut items);
534 let first_index = if has_self { 0 } else { 1 };
536 if context.config.reorder_imported_names() {
537 items[1..].sort_by(|a, b| {
538 let a = ImportItem::from_opt_str(a.item.as_ref());
539 let b = ImportItem::from_opt_str(b.item.as_ref());
544 let tactic = definitive_tactic(
545 &items[first_index..],
546 context.config.imports_layout(),
551 let ends_with_newline = context.config.imports_indent() == IndentStyle::Block
552 && tactic != DefinitiveListTactic::Horizontal;
554 let fmt = ListFormatting {
557 trailing_separator: if ends_with_newline {
558 context.config.trailing_comma()
560 SeparatorTactic::Never
562 separator_place: SeparatorPlace::Back,
564 ends_with_newline: ends_with_newline,
565 preserve_newline: true,
566 config: context.config,
568 let list_str = write_list(&items[first_index..], &fmt)?;
570 let result = if list_str.contains('\n') && context.config.imports_indent() == IndentStyle::Block
575 nested_shape.indent.to_string(context.config),
577 shape.indent.to_string(context.config)
580 format!("{}{{{}}}", path_str, list_str)
585 // Returns true when self item was found.
586 fn move_self_to_front(items: &mut Vec<ListItem>) -> bool {
589 .position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self"))
592 items[0] = items.remove(pos);
599 fn path_to_imported_ident(path: &ast::Path) -> ast::Ident {
600 path.segments.last().unwrap().identifier