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 config::IndentStyle;
19 use lists::{definitive_tactic, itemize_list, write_list, DefinitiveListTactic, ListFormatting,
20 ListItem, Separator, SeparatorTactic};
21 use rewrite::{Rewrite, RewriteContext};
22 use types::{rewrite_path, PathContext};
24 use visitor::FmtVisitor;
26 fn path_of(a: &ast::ViewPath_) -> &ast::Path {
28 ast::ViewPath_::ViewPathSimple(_, ref p) => p,
29 ast::ViewPath_::ViewPathGlob(ref p) => p,
30 ast::ViewPath_::ViewPathList(ref p, _) => p,
34 fn compare_path_segments(a: &ast::PathSegment, b: &ast::PathSegment) -> Ordering {
35 a.identifier.name.as_str().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.name.name.as_str();
50 let b_name_str = &*b.node.name.name.as_str();
51 let name_ordering = if a_name_str == "self" {
52 if b_name_str == "self" {
58 if b_name_str == "self" {
61 a_name_str.cmp(&b_name_str)
64 if name_ordering == Ordering::Equal {
66 Some(a_rename) => match b.node.rename {
67 Some(b_rename) => a_rename.name.as_str().cmp(&b_rename.name.as_str()),
68 None => Ordering::Greater,
70 None => Ordering::Less,
77 fn compare_path_list_item_lists(
78 a_items: &Vec<ast::PathListItem>,
79 b_items: &Vec<ast::PathListItem>,
81 let mut a = a_items.clone();
82 let mut b = b_items.clone();
83 a.sort_by(|a, b| compare_path_list_items(a, b));
84 b.sort_by(|a, b| compare_path_list_items(a, b));
85 for comparison_pair in a.iter().zip(b.iter()) {
86 let ord = compare_path_list_items(comparison_pair.0, comparison_pair.1);
87 if ord != Ordering::Equal {
94 fn compare_view_path_types(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering {
95 use syntax::ast::ViewPath_::*;
97 (&ViewPathSimple(..), &ViewPathSimple(..)) => Ordering::Equal,
98 (&ViewPathSimple(..), _) => Ordering::Less,
99 (&ViewPathGlob(_), &ViewPathSimple(..)) => Ordering::Greater,
100 (&ViewPathGlob(_), &ViewPathGlob(_)) => Ordering::Equal,
101 (&ViewPathGlob(_), &ViewPathList(..)) => Ordering::Less,
102 (&ViewPathList(_, ref a_items), &ViewPathList(_, ref b_items)) => {
103 compare_path_list_item_lists(a_items, b_items)
105 (&ViewPathList(..), _) => Ordering::Greater,
109 fn compare_view_paths(a: &ast::ViewPath_, b: &ast::ViewPath_) -> Ordering {
110 match compare_paths(path_of(a), path_of(b)) {
111 Ordering::Equal => compare_view_path_types(a, b),
116 fn compare_use_items(a: &ast::Item, b: &ast::Item) -> Option<Ordering> {
117 match (&a.node, &b.node) {
118 (&ast::ItemKind::Use(ref a_vp), &ast::ItemKind::Use(ref b_vp)) => {
119 Some(compare_view_paths(&a_vp.node, &b_vp.node))
125 // TODO (some day) remove unused imports, expand globs, compress many single
126 // imports into a list import.
128 fn rewrite_view_path_prefix(
130 context: &RewriteContext,
132 ) -> Option<String> {
133 let path_str = if path.segments.last().unwrap().identifier.to_string() == "self" &&
134 path.segments.len() > 1
136 let path = &ast::Path {
137 span: path.span.clone(),
138 segments: path.segments[..path.segments.len() - 1].to_owned(),
140 try_opt!(rewrite_path(
148 try_opt!(rewrite_path(
159 impl Rewrite for ast::ViewPath {
160 // Returns an empty string when the ViewPath is empty (like foo::bar::{})
161 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
163 ast::ViewPath_::ViewPathList(_, ref path_list) if path_list.is_empty() => {
166 ast::ViewPath_::ViewPathList(ref path, ref path_list) => {
167 rewrite_use_list(shape, path, path_list, self.span, context)
169 ast::ViewPath_::ViewPathGlob(ref path) => {
171 let prefix_shape = try_opt!(shape.sub_width(3));
172 let path_str = try_opt!(rewrite_view_path_prefix(path, context, prefix_shape));
173 Some(format!("{}::*", path_str))
175 ast::ViewPath_::ViewPathSimple(ident, ref path) => {
176 let ident_str = ident.to_string();
178 let prefix_shape = try_opt!(shape.sub_width(ident_str.len() + 4));
179 let path_str = try_opt!(rewrite_view_path_prefix(path, context, prefix_shape));
181 Some(if path.segments.last().unwrap().identifier == ident {
184 format!("{} as {}", path_str, ident_str)
191 impl<'a> FmtVisitor<'a> {
192 pub fn format_imports(&mut self, use_items: &[ptr::P<ast::Item>]) {
193 // Find the location immediately before the first use item in the run. This must not lie
194 // before the current `self.last_pos`
195 let pos_before_first_use_item = use_items
202 .map(|attr| attr.span.lo)
204 .unwrap_or(p_i.span.lo),
207 .unwrap_or(self.last_pos);
208 // Construct a list of pairs, each containing a `use` item and the start of span before
210 let mut last_pos_of_prev_use_item = pos_before_first_use_item;
211 let mut ordered_use_items = use_items
214 let new_item = (&*p_i, last_pos_of_prev_use_item);
215 last_pos_of_prev_use_item = p_i.span.hi;
218 .collect::<Vec<_>>();
219 let pos_after_last_use_item = last_pos_of_prev_use_item;
220 // Order the imports by view-path & other import path properties
221 ordered_use_items.sort_by(|a, b| compare_use_items(a.0, b.0).unwrap());
222 // First, output the span before the first import
223 let prev_span_str = self.snippet(utils::mk_sp(self.last_pos, pos_before_first_use_item));
224 // Look for purely trailing space at the start of the prefix snippet before a linefeed, or
225 // a prefix that's entirely horizontal whitespace.
226 let prefix_span_start = match prev_span_str.find('\n') {
227 Some(offset) if prev_span_str[..offset].trim().is_empty() => {
228 self.last_pos + BytePos(offset as u32)
230 None if prev_span_str.trim().is_empty() => pos_before_first_use_item,
233 // Look for indent (the line part preceding the use is all whitespace) and excise that
235 let span_end = match prev_span_str.rfind('\n') {
236 Some(offset) if prev_span_str[offset..].trim().is_empty() => {
237 self.last_pos + BytePos(offset as u32)
239 _ => pos_before_first_use_item,
242 self.last_pos = prefix_span_start;
243 self.format_missing(span_end);
244 for ordered in ordered_use_items {
245 // Fake out the formatter by setting `self.last_pos` to the appropriate location before
246 // each item before visiting it.
247 self.last_pos = ordered.1;
248 self.visit_item(ordered.0);
250 self.last_pos = pos_after_last_use_item;
253 pub fn format_import(
255 vis: &ast::Visibility,
258 attrs: &[ast::Attribute],
260 let vis = utils::format_visibility(vis);
261 // 4 = `use `, 1 = `;`
262 let rw = Shape::indented(self.block_indent, self.config)
263 .offset_left(vis.len() + 4)
264 .and_then(|shape| shape.sub_width(1))
265 .and_then(|shape| match vp.node {
266 // If we have an empty path with attributes attached, we want to skip erasing it
267 ast::ViewPath_::ViewPathList(ref path, ref path_list)
268 if path_list.is_empty() && !attrs.is_empty() =>
270 rewrite_path(&self.get_context(), PathContext::Import, None, path, shape)
271 .map(|path_str| format!("{}::{{}}", path_str))
273 _ => vp.rewrite(&self.get_context(), shape),
276 Some(ref s) if s.is_empty() => {
277 // Format up to last newline
278 let prev_span = utils::mk_sp(self.last_pos, source!(self, span).lo);
279 let span_end = match self.snippet(prev_span).rfind('\n') {
280 Some(offset) => self.last_pos + BytePos(offset as u32),
281 None => source!(self, span).lo,
283 self.format_missing(span_end);
284 self.last_pos = source!(self, span).hi;
287 let s = format!("{}use {};", vis, s);
288 self.format_missing_with_indent(source!(self, span).lo);
289 self.buffer.push_str(&s);
290 self.last_pos = source!(self, span).hi;
293 self.format_missing_with_indent(source!(self, span).lo);
294 self.format_missing(source!(self, span).hi);
300 fn rewrite_single_use_list(path_str: String, vpi: &ast::PathListItem) -> String {
301 let mut item_str = vpi.node.name.to_string();
302 if item_str == "self" {
303 item_str = "".to_owned();
305 let path_item_str = if path_str.is_empty() {
306 if item_str.is_empty() {
311 } else if item_str.is_empty() {
314 format!("{}::{}", path_str, item_str)
316 append_alias(path_item_str, vpi)
319 fn rewrite_path_item(vpi: &&ast::PathListItem) -> Option<String> {
320 Some(append_alias(vpi.node.name.to_string(), vpi))
323 fn append_alias(path_item_str: String, vpi: &ast::PathListItem) -> String {
324 match vpi.node.rename {
325 Some(rename) => format!("{} as {}", path_item_str, rename),
326 None => path_item_str,
330 #[derive(Eq, PartialEq)]
331 enum ImportItem<'a> {
332 // `self` or `self as a`
334 // name_one, name_two, ...
336 // NameOne, NameTwo, ...
338 // NAME_ONE, NAME_TWO, ...
340 // Failed to format the import item
344 impl<'a> ImportItem<'a> {
345 fn from_str(s: &str) -> ImportItem {
346 if s == "self" || s.starts_with("self as") {
347 ImportItem::SelfImport(s)
348 } else if s.chars().all(|c| c.is_lowercase() || c == '_' || c == ' ') {
349 ImportItem::SnakeCase(s)
350 } else if s.chars().all(|c| c.is_uppercase() || c == '_' || c == ' ') {
351 ImportItem::AllCaps(s)
353 ImportItem::CamelCase(s)
357 fn from_opt_str(s: Option<&String>) -> ImportItem {
358 s.map_or(ImportItem::Invalid, |s| ImportItem::from_str(s))
361 fn to_str(&self) -> Option<&str> {
363 ImportItem::SelfImport(s) |
364 ImportItem::SnakeCase(s) |
365 ImportItem::CamelCase(s) |
366 ImportItem::AllCaps(s) => Some(s),
367 ImportItem::Invalid => None,
371 fn to_u32(&self) -> u32 {
373 ImportItem::SelfImport(..) => 0,
374 ImportItem::SnakeCase(..) => 1,
375 ImportItem::CamelCase(..) => 2,
376 ImportItem::AllCaps(..) => 3,
377 ImportItem::Invalid => 4,
382 impl<'a> PartialOrd for ImportItem<'a> {
383 fn partial_cmp(&self, other: &ImportItem<'a>) -> Option<Ordering> {
384 Some(self.cmp(other))
388 impl<'a> Ord for ImportItem<'a> {
389 fn cmp(&self, other: &ImportItem<'a>) -> Ordering {
390 let res = self.to_u32().cmp(&other.to_u32());
391 if res != Ordering::Equal {
394 self.to_str().map_or(Ordering::Greater, |self_str| {
397 .map_or(Ordering::Less, |other_str| self_str.cmp(other_str))
402 // Pretty prints a multi-item import.
403 // Assumes that path_list.len() > 0.
407 path_list: &[ast::PathListItem],
409 context: &RewriteContext,
410 ) -> Option<String> {
411 // Returns a different option to distinguish `::foo` and `foo`
412 let path_str = try_opt!(rewrite_path(
420 match path_list.len() {
422 1 => return Some(rewrite_single_use_list(path_str, &path_list[0])),
426 let path_str = if path_str.is_empty() {
429 format!("{}::", path_str)
433 let remaining_width = shape.width.checked_sub(path_str.len() + 2).unwrap_or(0);
436 // Dummy value, see explanation below.
437 let mut items = vec![ListItem::from_str("")];
438 let iter = itemize_list(
445 context.codemap.span_after(span, "{"),
452 // We prefixed the item list with a dummy value so that we can
453 // potentially move "self" to the front of the vector without touching
454 // the rest of the items.
455 let has_self = move_self_to_front(&mut items);
456 let first_index = if has_self { 0 } else { 1 };
458 if context.config.reorder_imported_names() {
459 items[1..].sort_by(|a, b| {
460 let a = ImportItem::from_opt_str(a.item.as_ref());
461 let b = ImportItem::from_opt_str(b.item.as_ref());
466 let tactic = definitive_tactic(
467 &items[first_index..],
468 context.config.imports_layout(),
473 let nested_indent = match context.config.imports_indent() {
474 IndentStyle::Block => shape.indent.block_indent(context.config),
476 IndentStyle::Visual => shape.visual_indent(path_str.len() + 1).indent,
479 let nested_shape = match context.config.imports_indent() {
480 IndentStyle::Block => Shape::indented(nested_indent, context.config),
481 IndentStyle::Visual => Shape::legacy(remaining_width, nested_indent),
484 let ends_with_newline = context.config.imports_indent() == IndentStyle::Block &&
485 tactic != DefinitiveListTactic::Horizontal;
487 let fmt = ListFormatting {
490 trailing_separator: if ends_with_newline {
491 context.config.trailing_comma()
493 SeparatorTactic::Never
496 ends_with_newline: ends_with_newline,
497 preserve_newline: true,
498 config: context.config,
500 let list_str = try_opt!(write_list(&items[first_index..], &fmt));
502 let result = if list_str.contains('\n') && context.config.imports_indent() == IndentStyle::Block
507 nested_shape.indent.to_string(context.config),
509 shape.indent.to_string(context.config)
512 format!("{}{{{}}}", path_str, list_str)
517 // Returns true when self item was found.
518 fn move_self_to_front(items: &mut Vec<ListItem>) -> bool {
521 .position(|item| item.item.as_ref().map(|x| &x[..]) == Some("self"))
524 items[0] = items.remove(pos);