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 span_end = match self.snippet(prev_span).rfind('\n') {
318 Some(offset) => self.last_pos + BytePos(offset as u32),
319 None => source!(self, span).lo(),
321 self.format_missing(span_end);
322 self.last_pos = source!(self, span).hi();
325 self.format_missing_with_indent(source!(self, span).lo());
327 self.last_pos = source!(self, span).hi();
330 self.format_missing_with_indent(source!(self, span).lo());
331 self.format_missing(source!(self, span).hi());
337 fn rewrite_nested_use_tree_single(
338 context: &RewriteContext,
342 ) -> Option<String> {
344 ast::UseTreeKind::Simple(rename) => {
345 let ident = path_to_imported_ident(&tree.prefix);
346 let mut item_str = rewrite_prefix(&tree.prefix, context, shape)?;
347 if item_str == "self" {
348 item_str = "".to_owned();
351 let path_item_str = if path_str.is_empty() {
352 if item_str.is_empty() {
357 } else if item_str.is_empty() {
360 format!("{}::{}", path_str, item_str)
363 Some(if ident == rename {
366 format!("{} as {}", path_item_str, rename)
369 ast::UseTreeKind::Glob | ast::UseTreeKind::Nested(..) => {
371 let nested_shape = shape.offset_left(path_str.len() + 2)?;
372 tree.rewrite(context, nested_shape)
373 .map(|item| format!("{}::{}", path_str, item))
378 #[derive(Eq, PartialEq)]
379 enum ImportItem<'a> {
380 // `self` or `self as a`
382 // name_one, name_two, ...
384 // NameOne, NameTwo, ...
386 // NAME_ONE, NAME_TWO, ...
388 // Failed to format the import item
392 impl<'a> ImportItem<'a> {
393 fn from_str(s: &str) -> ImportItem {
394 if s == "self" || s.starts_with("self as") {
395 ImportItem::SelfImport(s)
396 } else if s.chars().all(|c| c.is_lowercase() || c == '_' || c == ' ') {
397 ImportItem::SnakeCase(s)
398 } else if s.chars().all(|c| c.is_uppercase() || c == '_' || c == ' ') {
399 ImportItem::AllCaps(s)
401 ImportItem::CamelCase(s)
405 fn from_opt_str(s: Option<&String>) -> ImportItem {
406 s.map_or(ImportItem::Invalid, |s| ImportItem::from_str(s))
409 fn to_str(&self) -> Option<&str> {
411 ImportItem::SelfImport(s)
412 | ImportItem::SnakeCase(s)
413 | ImportItem::CamelCase(s)
414 | ImportItem::AllCaps(s) => Some(s),
415 ImportItem::Invalid => None,
419 fn to_u32(&self) -> u32 {
421 ImportItem::SelfImport(..) => 0,
422 ImportItem::SnakeCase(..) => 1,
423 ImportItem::CamelCase(..) => 2,
424 ImportItem::AllCaps(..) => 3,
425 ImportItem::Invalid => 4,
430 impl<'a> PartialOrd for ImportItem<'a> {
431 fn partial_cmp(&self, other: &ImportItem<'a>) -> Option<Ordering> {
432 Some(self.cmp(other))
436 impl<'a> Ord for ImportItem<'a> {
437 fn cmp(&self, other: &ImportItem<'a>) -> Ordering {
438 let res = self.to_u32().cmp(&other.to_u32());
439 if res != Ordering::Equal {
442 self.to_str().map_or(Ordering::Greater, |self_str| {
445 .map_or(Ordering::Less, |other_str| self_str.cmp(other_str))
450 // Pretty prints a multi-item import.
451 // If the path list is empty, it leaves the braces empty.
452 fn rewrite_nested_use_tree(
455 trees: &[(ast::UseTree, ast::NodeId)],
457 context: &RewriteContext,
458 ) -> Option<String> {
459 // Returns a different option to distinguish `::foo` and `foo`
460 let path_str = rewrite_path(context, PathContext::Import, None, path, shape)?;
464 let shape = shape.offset_left(path_str.len() + 3)?;
465 return rewrite_path(context, PathContext::Import, None, path, shape)
466 .map(|path_str| format!("{}::{{}}", path_str));
469 return rewrite_nested_use_tree_single(context, &path_str, &trees[0].0, shape);
474 let path_str = if path_str.is_empty() {
477 format!("{}::", path_str)
481 let remaining_width = shape.width.checked_sub(path_str.len() + 2).unwrap_or(0);
482 let nested_indent = match context.config.imports_indent() {
483 IndentStyle::Block => shape.indent.block_indent(context.config),
485 IndentStyle::Visual => shape.visual_indent(path_str.len() + 1).indent,
488 let nested_shape = match context.config.imports_indent() {
489 IndentStyle::Block => Shape::indented(nested_indent, context.config).sub_width(1)?,
490 IndentStyle::Visual => Shape::legacy(remaining_width, nested_indent),
494 // Dummy value, see explanation below.
495 let mut items = vec![ListItem::from_str("")];
496 let iter = itemize_list(
498 trees.iter().map(|tree| &tree.0),
501 |tree| tree.span.lo(),
502 |tree| tree.span.hi(),
503 |tree| tree.rewrite(context, nested_shape),
504 context.codemap.span_after(span, "{"),
512 // We prefixed the item list with a dummy value so that we can
513 // potentially move "self" to the front of the vector without touching
514 // the rest of the items.
515 let has_self = move_self_to_front(&mut items);
516 let first_index = if has_self { 0 } else { 1 };
518 if context.config.reorder_imported_names() {
519 items[1..].sort_by(|a, b| {
520 let a = ImportItem::from_opt_str(a.item.as_ref());
521 let b = ImportItem::from_opt_str(b.item.as_ref());
526 let tactic = definitive_tactic(
527 &items[first_index..],
528 context.config.imports_layout(),
533 let ends_with_newline = context.config.imports_indent() == IndentStyle::Block
534 && tactic != DefinitiveListTactic::Horizontal;
536 let fmt = ListFormatting {
539 trailing_separator: if ends_with_newline {
540 context.config.trailing_comma()
542 SeparatorTactic::Never
544 separator_place: SeparatorPlace::Back,
546 ends_with_newline: ends_with_newline,
547 preserve_newline: true,
548 config: context.config,
550 let list_str = write_list(&items[first_index..], &fmt)?;
552 let result = if list_str.contains('\n') && context.config.imports_indent() == IndentStyle::Block
557 nested_shape.indent.to_string(context.config),
559 shape.indent.to_string(context.config)
562 format!("{}{{{}}}", path_str, list_str)
567 // Returns true when self item was found.
568 fn move_self_to_front(items: &mut Vec<ListItem>) -> bool {
571 .position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self"))
574 items[0] = items.remove(pos);
581 fn path_to_imported_ident(path: &ast::Path) -> ast::Ident {
582 path.segments.last().unwrap().identifier