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) -> Option<Ordering> {
109 match (&a.node, &b.node) {
110 (&ast::ItemKind::Use(ref a_tree), &ast::ItemKind::Use(ref b_tree)) => {
111 Some(compare_use_trees(a_tree, b_tree, false))
113 (&ast::ItemKind::ExternCrate(ref a_name), &ast::ItemKind::ExternCrate(ref b_name)) => {
114 // `extern crate foo as bar;`
115 // ^^^ Comparing this.
117 a_name.map_or_else(|| a.ident.name.as_str(), |symbol| symbol.as_str());
119 b_name.map_or_else(|| b.ident.name.as_str(), |symbol| symbol.as_str());
120 let result = a_orig_name.cmp(&b_orig_name);
121 if result != Ordering::Equal {
125 // `extern crate foo as bar;`
126 // ^^^ Comparing this.
127 let result = match (a_name, b_name) {
128 (Some(..), None) => Ordering::Greater,
129 (None, Some(..)) => Ordering::Less,
130 (None, None) => Ordering::Equal,
131 (Some(..), Some(..)) => a.ident.name.cmp(&b.ident.name),
139 // TODO (some day) remove unused imports, expand globs, compress many single
140 // imports into a list import.
142 fn rewrite_prefix(path: &ast::Path, context: &RewriteContext, shape: Shape) -> Option<String> {
143 if path.segments.len() > 1 && path_to_imported_ident(path).to_string() == "self" {
144 let path = &ast::Path {
146 segments: path.segments[..path.segments.len() - 1].to_owned(),
148 rewrite_path(context, PathContext::Import, None, path, shape)
150 rewrite_path(context, PathContext::Import, None, path, shape)
154 impl Rewrite for ast::UseTree {
155 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
157 ast::UseTreeKind::Nested(ref items) => {
158 rewrite_nested_use_tree(shape, &self.prefix, items, self.span, context)
160 ast::UseTreeKind::Glob => {
161 let prefix_shape = shape.sub_width(3)?;
163 if !self.prefix.segments.is_empty() {
164 let path_str = rewrite_prefix(&self.prefix, context, prefix_shape)?;
165 Some(format!("{}::*", path_str))
170 ast::UseTreeKind::Simple(ident) => {
171 let ident_str = ident.to_string();
174 let is_same_name_bind = path_to_imported_ident(&self.prefix) == ident;
175 let prefix_shape = if is_same_name_bind {
178 shape.sub_width(ident_str.len() + 4)?
180 let path_str = rewrite_prefix(&self.prefix, context, prefix_shape)
181 .unwrap_or_else(|| context.snippet(self.prefix.span).to_owned());
183 if is_same_name_bind {
186 Some(format!("{} as {}", path_str, ident_str))
193 fn is_unused_import(tree: &ast::UseTree, attrs: &[ast::Attribute]) -> bool {
194 attrs.is_empty() && is_unused_import_inner(tree)
197 fn is_unused_import_inner(tree: &ast::UseTree) -> bool {
199 ast::UseTreeKind::Nested(ref items) => match items.len() {
201 1 => is_unused_import_inner(&items[0].0),
208 // Rewrite `use foo;` WITHOUT attributes.
210 context: &RewriteContext,
211 vis: &ast::Visibility,
213 attrs: &[ast::Attribute],
215 ) -> Option<String> {
216 let vis = format_visibility(vis);
217 // 4 = `use `, 1 = `;`
219 .offset_left(vis.len() + 4)
220 .and_then(|shape| shape.sub_width(1))
222 // If we have an empty nested group with no attributes, we erase it
223 if is_unused_import(tree, attrs) {
226 tree.rewrite(context, shape)
230 Some(ref s) if !s.is_empty() => Some(format!("{}use {};", vis, s)),
236 context: &RewriteContext,
237 use_items: &[&ast::Item],
240 ) -> Option<String> {
241 let items = itemize_list(
246 |item| item.span().lo(),
247 |item| item.span().hi(),
249 let attrs_str = item.attrs.rewrite(context, shape)?;
251 let missed_span = if item.attrs.is_empty() {
252 mk_sp(item.span.lo(), item.span.lo())
254 mk_sp(item.attrs.last().unwrap().span.hi(), item.span.lo())
257 let item_str = match item.node {
258 ast::ItemKind::Use(ref tree) => {
259 rewrite_import(context, &item.vis, tree, &item.attrs, shape)?
261 ast::ItemKind::ExternCrate(..) => rewrite_extern_crate(context, item)?,
265 combine_strs_with_missing_comments(
278 let mut item_pair_vec: Vec<_> = items.zip(use_items.iter()).collect();
279 item_pair_vec.sort_by(|a, b| compare_use_items(a.1, b.1).unwrap());
280 let item_vec: Vec<_> = item_pair_vec.into_iter().map(|pair| pair.0).collect();
282 let fmt = ListFormatting {
283 tactic: DefinitiveListTactic::Vertical,
285 trailing_separator: SeparatorTactic::Never,
286 separator_place: SeparatorPlace::Back,
288 ends_with_newline: true,
289 preserve_newline: false,
290 config: context.config,
293 write_list(&item_vec, &fmt)
296 impl<'a> FmtVisitor<'a> {
297 pub fn format_imports(&mut self, use_items: &[&ast::Item]) {
298 if use_items.is_empty() {
302 let lo = use_items.first().unwrap().span().lo();
303 let hi = use_items.last().unwrap().span().hi();
304 let span = mk_sp(lo, hi);
305 let rw = rewrite_imports(&self.get_context(), use_items, self.shape(), span);
306 self.push_rewrite(span, rw);
309 pub fn format_import(&mut self, item: &ast::Item, tree: &ast::UseTree) {
310 let span = item.span;
311 let shape = self.shape();
312 let rw = rewrite_import(&self.get_context(), &item.vis, tree, &item.attrs, shape);
314 Some(ref s) if s.is_empty() => {
315 // Format up to last newline
316 let prev_span = mk_sp(self.last_pos, source!(self, span).lo());
317 let trimmed_snippet = self.snippet(prev_span).trim_right();
318 let span_end = self.last_pos + BytePos(trimmed_snippet.len() as u32);
319 self.format_missing(span_end);
320 // We have an excessive newline from the removed import.
321 if self.buffer.ends_with('\n') {
323 self.line_number -= 1;
325 self.last_pos = source!(self, span).hi();
328 self.format_missing_with_indent(source!(self, span).lo());
330 self.last_pos = source!(self, span).hi();
333 self.format_missing_with_indent(source!(self, span).lo());
334 self.format_missing(source!(self, span).hi());
340 fn rewrite_nested_use_tree_single(
341 context: &RewriteContext,
345 ) -> Option<String> {
347 ast::UseTreeKind::Simple(rename) => {
348 let ident = path_to_imported_ident(&tree.prefix);
349 let mut item_str = rewrite_prefix(&tree.prefix, context, shape)?;
350 if item_str == "self" {
351 item_str = "".to_owned();
354 let path_item_str = if path_str.is_empty() {
355 if item_str.is_empty() {
360 } else if item_str.is_empty() {
363 format!("{}::{}", path_str, item_str)
366 Some(if ident == rename {
369 format!("{} as {}", path_item_str, rename)
372 ast::UseTreeKind::Glob | ast::UseTreeKind::Nested(..) => {
374 let nested_shape = shape.offset_left(path_str.len() + 2)?;
375 tree.rewrite(context, nested_shape)
376 .map(|item| format!("{}::{}", path_str, item))
381 #[derive(Eq, PartialEq)]
382 enum ImportItem<'a> {
383 // `self` or `self as a`
385 // name_one, name_two, ...
387 // NameOne, NameTwo, ...
389 // NAME_ONE, NAME_TWO, ...
391 // Failed to format the import item
395 impl<'a> ImportItem<'a> {
396 fn from_str(s: &str) -> ImportItem {
397 if s == "self" || s.starts_with("self as") {
398 ImportItem::SelfImport(s)
399 } else if s.chars().all(|c| c.is_lowercase() || c == '_' || c == ' ') {
400 ImportItem::SnakeCase(s)
401 } else if s.chars().all(|c| c.is_uppercase() || c == '_' || c == ' ') {
402 ImportItem::AllCaps(s)
404 ImportItem::CamelCase(s)
408 fn from_opt_str(s: Option<&String>) -> ImportItem {
409 s.map_or(ImportItem::Invalid, |s| ImportItem::from_str(s))
412 fn to_str(&self) -> Option<&str> {
414 ImportItem::SelfImport(s)
415 | ImportItem::SnakeCase(s)
416 | ImportItem::CamelCase(s)
417 | ImportItem::AllCaps(s) => Some(s),
418 ImportItem::Invalid => None,
422 fn to_u32(&self) -> u32 {
424 ImportItem::SelfImport(..) => 0,
425 ImportItem::SnakeCase(..) => 1,
426 ImportItem::CamelCase(..) => 2,
427 ImportItem::AllCaps(..) => 3,
428 ImportItem::Invalid => 4,
433 impl<'a> PartialOrd for ImportItem<'a> {
434 fn partial_cmp(&self, other: &ImportItem<'a>) -> Option<Ordering> {
435 Some(self.cmp(other))
439 impl<'a> Ord for ImportItem<'a> {
440 fn cmp(&self, other: &ImportItem<'a>) -> Ordering {
441 let res = self.to_u32().cmp(&other.to_u32());
442 if res != Ordering::Equal {
445 self.to_str().map_or(Ordering::Greater, |self_str| {
448 .map_or(Ordering::Less, |other_str| self_str.cmp(other_str))
453 // Pretty prints a multi-item import.
454 // If the path list is empty, it leaves the braces empty.
455 fn rewrite_nested_use_tree(
458 trees: &[(ast::UseTree, ast::NodeId)],
460 context: &RewriteContext,
461 ) -> Option<String> {
462 // Returns a different option to distinguish `::foo` and `foo`
463 let path_str = rewrite_path(context, PathContext::Import, None, path, shape)?;
467 let shape = shape.offset_left(path_str.len() + 3)?;
468 return rewrite_path(context, PathContext::Import, None, path, shape)
469 .map(|path_str| format!("{}::{{}}", path_str));
472 return rewrite_nested_use_tree_single(context, &path_str, &trees[0].0, shape);
477 let path_str = if path_str.is_empty() {
480 format!("{}::", path_str)
484 let remaining_width = shape.width.checked_sub(path_str.len() + 2).unwrap_or(0);
485 let nested_indent = match context.config.imports_indent() {
486 IndentStyle::Block => shape.indent.block_indent(context.config),
488 IndentStyle::Visual => shape.visual_indent(path_str.len() + 1).indent,
491 let nested_shape = match context.config.imports_indent() {
492 IndentStyle::Block => Shape::indented(nested_indent, context.config).sub_width(1)?,
493 IndentStyle::Visual => Shape::legacy(remaining_width, nested_indent),
497 // Dummy value, see explanation below.
498 let mut items = vec![ListItem::from_str("")];
499 let iter = itemize_list(
501 trees.iter().map(|tree| &tree.0),
504 |tree| tree.span.lo(),
505 |tree| tree.span.hi(),
506 |tree| tree.rewrite(context, nested_shape),
507 context.codemap.span_after(span, "{"),
515 // We prefixed the item list with a dummy value so that we can
516 // potentially move "self" to the front of the vector without touching
517 // the rest of the items.
518 let has_self = move_self_to_front(&mut items);
519 let first_index = if has_self { 0 } else { 1 };
521 if context.config.reorder_imported_names() {
522 items[1..].sort_by(|a, b| {
523 let a = ImportItem::from_opt_str(a.item.as_ref());
524 let b = ImportItem::from_opt_str(b.item.as_ref());
529 let tactic = definitive_tactic(
530 &items[first_index..],
531 context.config.imports_layout(),
536 let ends_with_newline = context.config.imports_indent() == IndentStyle::Block
537 && tactic != DefinitiveListTactic::Horizontal;
539 let fmt = ListFormatting {
542 trailing_separator: if ends_with_newline {
543 context.config.trailing_comma()
545 SeparatorTactic::Never
547 separator_place: SeparatorPlace::Back,
549 ends_with_newline: ends_with_newline,
550 preserve_newline: true,
551 config: context.config,
553 let list_str = write_list(&items[first_index..], &fmt)?;
555 let result = if list_str.contains('\n') && context.config.imports_indent() == IndentStyle::Block
560 nested_shape.indent.to_string(context.config),
562 shape.indent.to_string(context.config)
565 format!("{}{{{}}}", path_str, list_str)
570 // Returns true when self item was found.
571 fn move_self_to_front(items: &mut Vec<ListItem>) -> bool {
574 .position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self"))
577 items[0] = items.remove(pos);
584 fn path_to_imported_ident(path: &ast::Path) -> ast::Ident {
585 path.segments.last().unwrap().identifier