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.
13 use strings::string_buffer::StringBuffer;
14 use syntax::{ast, visit};
15 use syntax::attr::HasAttrs;
16 use syntax::codemap::{self, BytePos, CodeMap, Pos, Span};
17 use syntax::parse::ParseSess;
20 use codemap::{LineRangeUtils, SpanUtils};
21 use comment::{contains_comment, recover_missing_comment_in_span, CodeCharKind, CommentCodeSlices,
23 use comment::rewrite_comment;
24 use config::{BraceStyle, Config};
25 use items::{format_impl, format_struct, format_struct_struct, format_trait,
26 rewrite_associated_impl_type, rewrite_associated_type, rewrite_static,
28 use lists::{itemize_list, write_list, DefinitiveListTactic, ListFormatting, SeparatorPlace,
30 use macros::{rewrite_macro, MacroPosition};
32 use rewrite::{Rewrite, RewriteContext};
33 use shape::{Indent, Shape};
34 use utils::{self, contains_skip, inner_attributes, mk_sp, ptr_vec_to_ref_vec};
36 fn is_use_item(item: &ast::Item) -> bool {
38 ast::ItemKind::Use(_) => true,
43 fn is_extern_crate(item: &ast::Item) -> bool {
45 ast::ItemKind::ExternCrate(..) => true,
50 pub struct FmtVisitor<'a> {
51 pub parse_session: &'a ParseSess,
52 pub codemap: &'a CodeMap,
53 pub buffer: StringBuffer,
54 pub last_pos: BytePos,
55 // FIXME: use an RAII util or closure for indenting
56 pub block_indent: Indent,
57 pub config: &'a Config,
58 pub is_if_else_block: bool,
61 impl<'a> FmtVisitor<'a> {
62 pub fn shape(&self) -> Shape {
63 Shape::indented(self.block_indent, self.config)
66 fn visit_stmt(&mut self, stmt: &ast::Stmt) {
68 "visit_stmt: {:?} {:?}",
69 self.codemap.lookup_char_pos(stmt.span.lo()),
70 self.codemap.lookup_char_pos(stmt.span.hi())
74 ast::StmtKind::Item(ref item) => {
75 self.visit_item(item);
77 ast::StmtKind::Local(..) | ast::StmtKind::Expr(..) | ast::StmtKind::Semi(..) => {
78 let rewrite = stmt.rewrite(&self.get_context(), self.shape());
79 self.push_rewrite(stmt.span(), rewrite)
81 ast::StmtKind::Mac(ref mac) => {
82 let (ref mac, _macro_style, ref attrs) = **mac;
83 if self.visit_attrs(attrs, ast::AttrStyle::Outer) {
84 self.push_rewrite(stmt.span(), None);
86 self.visit_mac(mac, None, MacroPosition::Statement);
88 self.format_missing(stmt.span.hi());
93 pub fn visit_block(&mut self, b: &ast::Block, inner_attrs: Option<&[ast::Attribute]>) {
95 "visit_block: {:?} {:?}",
96 self.codemap.lookup_char_pos(b.span.lo()),
97 self.codemap.lookup_char_pos(b.span.hi())
100 // Check if this block has braces.
101 let snippet = self.snippet(b.span);
102 let has_braces = snippet.starts_with('{') || snippet.starts_with("unsafe");
103 let brace_compensation = if has_braces { BytePos(1) } else { BytePos(0) };
105 self.last_pos = self.last_pos + brace_compensation;
106 self.block_indent = self.block_indent.block_indent(self.config);
107 self.buffer.push_str("{");
109 if self.config.remove_blank_lines_at_start_or_end_of_block() {
110 if let Some(first_stmt) = b.stmts.first() {
111 let attr_lo = inner_attrs
113 inner_attributes(attrs).first().map(|attr| attr.span.lo())
116 // Attributes for an item in a statement position
117 // do not belong to the statement. (rust-lang/rust#34459)
118 if let ast::StmtKind::Item(ref item) = first_stmt.node {
121 first_stmt.attrs().first()
123 // Some stmts can have embedded attributes.
124 // e.g. `match { #![attr] ... }`
125 let attr_lo = attr.span.lo();
126 if attr_lo < first_stmt.span.lo() {
134 let snippet = self.snippet(mk_sp(
136 attr_lo.unwrap_or(first_stmt.span.lo()),
138 let len = CommentCodeSlices::new(&snippet).nth(0).and_then(
139 |(kind, _, s)| if kind == CodeCharKind::Normal {
145 if let Some(len) = len {
146 self.last_pos = self.last_pos + BytePos::from_usize(len);
151 // Format inner attributes if available.
152 if let Some(attrs) = inner_attrs {
153 self.visit_attrs(attrs, ast::AttrStyle::Inner);
156 self.walk_block_stmts(b);
158 if !b.stmts.is_empty() {
159 if let Some(expr) = utils::stmt_expr(&b.stmts[b.stmts.len() - 1]) {
160 if utils::semicolon_for_expr(&self.get_context(), expr) {
161 self.buffer.push_str(";");
166 let mut remove_len = BytePos(0);
167 if self.config.remove_blank_lines_at_start_or_end_of_block() {
168 if let Some(stmt) = b.stmts.last() {
169 let snippet = self.snippet(mk_sp(
171 source!(self, b.span).hi() - brace_compensation,
173 let len = CommentCodeSlices::new(&snippet)
175 .and_then(|(kind, _, s)| {
176 if kind == CodeCharKind::Normal && s.trim().is_empty() {
182 if let Some(len) = len {
183 remove_len = BytePos::from_usize(len);
188 let mut unindent_comment = self.is_if_else_block && !b.stmts.is_empty();
189 if unindent_comment {
190 let end_pos = source!(self, b.span).hi() - brace_compensation - remove_len;
191 let snippet = self.snippet(mk_sp(self.last_pos, end_pos));
192 unindent_comment = snippet.contains("//") || snippet.contains("/*");
194 // FIXME: we should compress any newlines here to just one
195 if unindent_comment {
196 self.block_indent = self.block_indent.block_unindent(self.config);
198 self.format_missing_with_indent(
199 source!(self, b.span).hi() - brace_compensation - remove_len,
201 if unindent_comment {
202 self.block_indent = self.block_indent.block_indent(self.config);
204 self.close_block(unindent_comment);
205 self.last_pos = source!(self, b.span).hi();
208 // FIXME: this is a terrible hack to indent the comments between the last
209 // item in the block and the closing brace to the block's level.
210 // The closing brace itself, however, should be indented at a shallower
212 fn close_block(&mut self, unindent_comment: bool) {
213 let total_len = self.buffer.len;
214 let chars_too_many = if unindent_comment {
216 } else if self.config.hard_tabs() {
219 self.config.tab_spaces()
221 self.buffer.truncate(total_len - chars_too_many);
222 self.buffer.push_str("}");
223 self.block_indent = self.block_indent.block_unindent(self.config);
226 // Note that this only gets called for function definitions. Required methods
227 // on traits do not get handled here.
234 defaultness: ast::Defaultness,
235 inner_attrs: Option<&[ast::Attribute]>,
237 let indent = self.block_indent;
239 let rewrite = match fk {
240 visit::FnKind::ItemFn(ident, generics, unsafety, constness, abi, vis, b) => {
252 mk_sp(s.lo(), b.span.lo()),
256 visit::FnKind::Method(ident, sig, vis, b) => {
267 vis.unwrap_or(&ast::Visibility::Inherited),
268 mk_sp(s.lo(), b.span.lo()),
272 visit::FnKind::Closure(_) => unreachable!(),
275 if let Some(fn_str) = rewrite {
276 self.format_missing_with_indent(source!(self, s).lo());
277 self.buffer.push_str(&fn_str);
278 if let Some(c) = fn_str.chars().last() {
280 self.last_pos = source!(self, block.span).hi();
285 self.format_missing(source!(self, block.span).lo());
288 self.last_pos = source!(self, block.span).lo();
289 self.visit_block(block, inner_attrs)
292 pub fn visit_item(&mut self, item: &ast::Item) {
293 skip_out_of_file_lines_range_visitor!(self, item.span);
295 // This is where we bail out if there is a skip attribute. This is only
296 // complex in the module case. It is complex because the module could be
297 // in a separate file and there might be attributes in both files, but
298 // the AST lumps them all together.
300 let mut attrs = &item.attrs;
302 ast::ItemKind::Mod(ref m) => {
303 let outer_file = self.codemap.lookup_char_pos(item.span.lo()).file;
304 let inner_file = self.codemap.lookup_char_pos(m.inner.lo()).file;
305 if outer_file.name == inner_file.name {
306 // Module is inline, in this case we treat modules like any
308 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
309 self.push_rewrite(item.span, None);
312 } else if contains_skip(&item.attrs) {
313 // Module is not inline, but should be skipped.
316 // Module is not inline and should not be skipped. We want
317 // to process only the attributes in the current file.
318 filterd_attrs = item.attrs
321 let attr_file = self.codemap.lookup_char_pos(a.span.lo()).file;
322 if attr_file.name == outer_file.name {
328 .collect::<Vec<_>>();
329 // Assert because if we should skip it should be caught by
331 assert!(!self.visit_attrs(&filterd_attrs, ast::AttrStyle::Outer));
332 attrs = &filterd_attrs;
335 _ => if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
336 self.push_rewrite(item.span, None);
342 ast::ItemKind::Use(ref vp) => self.format_import(item, vp),
343 ast::ItemKind::Impl(..) => {
344 let snippet = self.snippet(item.span);
345 let where_span_end = snippet
346 .find_uncommented("{")
347 .map(|x| (BytePos(x as u32)) + source!(self, item.span).lo());
348 let rw = format_impl(&self.get_context(), item, self.block_indent, where_span_end);
349 self.push_rewrite(item.span, rw);
351 ast::ItemKind::Trait(..) => {
352 let rw = format_trait(&self.get_context(), item, self.block_indent);
353 self.push_rewrite(item.span, rw);
355 ast::ItemKind::ExternCrate(_) => {
356 let rw = rewrite_extern_crate(&self.get_context(), item);
357 self.push_rewrite(item.span, rw);
359 ast::ItemKind::Struct(ref def, ref generics) => {
360 let rewrite = format_struct(
370 ).map(|s| match *def {
371 ast::VariantData::Tuple(..) => s + ";",
374 self.push_rewrite(item.span, rewrite);
376 ast::ItemKind::Enum(ref def, ref generics) => {
377 self.format_missing_with_indent(source!(self, item.span).lo());
378 self.visit_enum(item.ident, &item.vis, def, generics, item.span);
379 self.last_pos = source!(self, item.span).hi();
381 ast::ItemKind::Mod(ref module) => {
382 self.format_missing_with_indent(source!(self, item.span).lo());
383 self.format_mod(module, &item.vis, item.span, item.ident, attrs);
385 ast::ItemKind::Mac(ref mac) => {
386 self.visit_mac(mac, Some(item.ident), MacroPosition::Item);
388 ast::ItemKind::ForeignMod(ref foreign_mod) => {
389 self.format_missing_with_indent(source!(self, item.span).lo());
390 self.format_foreign_mod(foreign_mod, item.span);
392 ast::ItemKind::Static(ref ty, mutability, ref expr) => {
393 let rewrite = rewrite_static(
404 self.push_rewrite(item.span, rewrite);
406 ast::ItemKind::Const(ref ty, ref expr) => {
407 let rewrite = rewrite_static(
412 ast::Mutability::Immutable,
418 self.push_rewrite(item.span, rewrite);
420 ast::ItemKind::DefaultImpl(..) => {
421 // FIXME(#78): format impl definitions.
423 ast::ItemKind::Fn(ref decl, unsafety, constness, abi, ref generics, ref body) => {
425 visit::FnKind::ItemFn(
437 ast::Defaultness::Final,
441 ast::ItemKind::Ty(ref ty, ref generics) => {
442 let rewrite = rewrite_type_alias(
451 self.push_rewrite(item.span, rewrite);
453 ast::ItemKind::Union(ref def, ref generics) => {
454 let rewrite = format_struct_struct(
465 self.push_rewrite(item.span, rewrite);
467 ast::ItemKind::GlobalAsm(..) => {
468 let snippet = Some(self.snippet(item.span));
469 self.push_rewrite(item.span, snippet);
471 ast::ItemKind::MacroDef(..) => {
472 // FIXME(#1539): macros 2.0
473 let mac_snippet = Some(self.snippet(item.span));
474 self.push_rewrite(item.span, mac_snippet);
479 pub fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
480 skip_out_of_file_lines_range_visitor!(self, ti.span);
482 if self.visit_attrs(&ti.attrs, ast::AttrStyle::Outer) {
483 self.push_rewrite(ti.span, None);
488 ast::TraitItemKind::Const(ref ty, ref expr_opt) => {
489 let rewrite = rewrite_static(
491 &ast::Visibility::Inherited,
494 ast::Mutability::Immutable,
500 self.push_rewrite(ti.span, rewrite);
502 ast::TraitItemKind::Method(ref sig, None) => {
503 let indent = self.block_indent;
504 let rewrite = self.rewrite_required_fn(indent, ti.ident, sig, ti.span);
505 self.push_rewrite(ti.span, rewrite);
507 ast::TraitItemKind::Method(ref sig, Some(ref body)) => {
509 visit::FnKind::Method(ti.ident, sig, None, body),
513 ast::Defaultness::Final,
517 ast::TraitItemKind::Type(ref type_param_bounds, ref type_default) => {
518 let rewrite = rewrite_associated_type(
520 type_default.as_ref(),
521 Some(type_param_bounds),
525 self.push_rewrite(ti.span, rewrite);
527 ast::TraitItemKind::Macro(ref mac) => {
528 self.visit_mac(mac, Some(ti.ident), MacroPosition::Item);
533 pub fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
534 skip_out_of_file_lines_range_visitor!(self, ii.span);
536 if self.visit_attrs(&ii.attrs, ast::AttrStyle::Outer) {
537 self.push_rewrite(ii.span, None);
542 ast::ImplItemKind::Method(ref sig, ref body) => {
544 visit::FnKind::Method(ii.ident, sig, Some(&ii.vis), body),
552 ast::ImplItemKind::Const(ref ty, ref expr) => {
553 let rewrite = rewrite_static(
558 ast::Mutability::Immutable,
564 self.push_rewrite(ii.span, rewrite);
566 ast::ImplItemKind::Type(ref ty) => {
567 let rewrite = rewrite_associated_impl_type(
575 self.push_rewrite(ii.span, rewrite);
577 ast::ImplItemKind::Macro(ref mac) => {
578 self.visit_mac(mac, Some(ii.ident), MacroPosition::Item);
583 fn visit_mac(&mut self, mac: &ast::Mac, ident: Option<ast::Ident>, pos: MacroPosition) {
584 skip_out_of_file_lines_range_visitor!(self, mac.span);
587 let shape = self.shape().sub_width(1).unwrap();
588 let rewrite = rewrite_macro(mac, ident, &self.get_context(), shape, pos);
589 self.push_rewrite(mac.span, rewrite);
592 pub fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
593 self.format_missing_with_indent(source!(self, span).lo());
594 let result = rewrite.unwrap_or_else(|| self.snippet(span));
595 self.buffer.push_str(&result);
596 self.last_pos = source!(self, span).hi();
599 pub fn from_codemap(parse_session: &'a ParseSess, config: &'a Config) -> FmtVisitor<'a> {
601 parse_session: parse_session,
602 codemap: parse_session.codemap(),
603 buffer: StringBuffer::new(),
604 last_pos: BytePos(0),
605 block_indent: Indent::empty(),
607 is_if_else_block: false,
611 pub fn snippet(&self, span: Span) -> String {
612 match self.codemap.span_to_snippet(span) {
616 "Couldn't make snippet for span {:?}->{:?}",
617 self.codemap.lookup_char_pos(span.lo()),
618 self.codemap.lookup_char_pos(span.hi())
625 // Returns true if we should skip the following item.
626 pub fn visit_attrs(&mut self, attrs: &[ast::Attribute], style: ast::AttrStyle) -> bool {
627 if contains_skip(attrs) {
631 let attrs: Vec<_> = attrs.iter().filter(|a| a.style == style).cloned().collect();
632 if attrs.is_empty() {
636 let rewrite = attrs.rewrite(&self.get_context(), self.shape());
637 let span = mk_sp(attrs[0].span.lo(), attrs[attrs.len() - 1].span.hi());
638 self.push_rewrite(span, rewrite);
643 fn reorder_items<F>(&mut self, items_left: &[&ast::Item], is_item: &F, in_group: bool) -> usize
645 F: Fn(&ast::Item) -> bool,
647 let mut last = self.codemap.lookup_line_range(items_left[0].span());
648 let item_length = items_left
651 is_item(&***ppi) && (!in_group || {
652 let current = self.codemap.lookup_line_range(ppi.span());
653 let in_same_group = current.lo < last.hi + 2;
659 let items = &items_left[..item_length];
661 let at_least_one_in_file_lines = items
663 .any(|item| !out_of_file_lines_range!(self, item.span));
665 if at_least_one_in_file_lines {
666 self.format_imports(items);
669 self.push_rewrite(item.span, None);
676 fn walk_items(&mut self, mut items_left: &[&ast::Item]) {
677 while !items_left.is_empty() {
678 // If the next item is a `use` declaration, then extract it and any subsequent `use`s
679 // to be potentially reordered within `format_imports`. Otherwise, just format the
680 // next item for output.
681 if self.config.reorder_imports() && is_use_item(&*items_left[0]) {
682 let used_items_len = self.reorder_items(
685 self.config.reorder_imports_in_group(),
687 let (_, rest) = items_left.split_at(used_items_len);
689 } else if self.config.reorder_extern_crates() && is_extern_crate(&*items_left[0]) {
690 let used_items_len = self.reorder_items(
693 self.config.reorder_extern_crates_in_group(),
695 let (_, rest) = items_left.split_at(used_items_len);
698 // `unwrap()` is safe here because we know `items_left`
699 // has elements from the loop condition
700 let (item, rest) = items_left.split_first().unwrap();
701 self.visit_item(item);
707 fn walk_mod_items(&mut self, m: &ast::Mod) {
708 self.walk_items(&ptr_vec_to_ref_vec(&m.items));
711 fn walk_stmts(&mut self, stmts: &[ast::Stmt]) {
712 fn to_stmt_item(stmt: &ast::Stmt) -> Option<&ast::Item> {
714 ast::StmtKind::Item(ref item) => Some(&**item),
719 if stmts.is_empty() {
723 // Extract leading `use ...;`.
724 let items: Vec<_> = stmts
726 .take_while(|stmt| to_stmt_item(stmt).is_some())
727 .filter_map(|stmt| to_stmt_item(stmt))
728 .take_while(|item| is_use_item(item))
731 if items.is_empty() {
732 self.visit_stmt(&stmts[0]);
733 self.walk_stmts(&stmts[1..]);
735 self.walk_items(&items);
736 self.walk_stmts(&stmts[items.len()..]);
740 fn walk_block_stmts(&mut self, b: &ast::Block) {
741 self.walk_stmts(&b.stmts)
747 vis: &ast::Visibility,
750 attrs: &[ast::Attribute],
752 // Decide whether this is an inline mod or an external mod.
753 let local_file_name = self.codemap.span_to_filename(s);
754 let inner_span = source!(self, m.inner);
755 let is_internal = !(inner_span.lo().0 == 0 && inner_span.hi().0 == 0)
756 && local_file_name == self.codemap.span_to_filename(inner_span);
758 self.buffer.push_str(&*utils::format_visibility(vis));
759 self.buffer.push_str("mod ");
760 self.buffer.push_str(&ident.to_string());
763 match self.config.item_brace_style() {
764 BraceStyle::AlwaysNextLine => self.buffer
765 .push_str(&format!("\n{}{{", self.block_indent.to_string(self.config))),
766 _ => self.buffer.push_str(" {"),
768 // Hackery to account for the closing }.
769 let mod_lo = self.codemap.span_after(source!(self, s), "{");
771 self.snippet(mk_sp(mod_lo, source!(self, m.inner).hi() - BytePos(1)));
772 let body_snippet = body_snippet.trim();
773 if body_snippet.is_empty() {
774 self.buffer.push_str("}");
776 self.last_pos = mod_lo;
777 self.block_indent = self.block_indent.block_indent(self.config);
778 self.visit_attrs(attrs, ast::AttrStyle::Inner);
779 self.walk_mod_items(m);
780 self.format_missing_with_indent(source!(self, m.inner).hi() - BytePos(1));
781 self.close_block(false);
783 self.last_pos = source!(self, m.inner).hi();
785 self.buffer.push_str(";");
786 self.last_pos = source!(self, s).hi();
790 pub fn format_separate_mod(&mut self, m: &ast::Mod, filemap: &codemap::FileMap) {
791 self.block_indent = Indent::empty();
792 self.walk_mod_items(m);
793 self.format_missing_with_indent(filemap.end_pos);
796 pub fn get_context(&self) -> RewriteContext {
798 parse_session: self.parse_session,
799 codemap: self.codemap,
803 is_if_else_block: false,
804 force_one_line_chain: false,
809 impl Rewrite for ast::NestedMetaItem {
810 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
812 ast::NestedMetaItemKind::MetaItem(ref meta_item) => meta_item.rewrite(context, shape),
813 ast::NestedMetaItemKind::Literal(..) => Some(context.snippet(self.span)),
818 impl Rewrite for ast::MetaItem {
819 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
820 Some(match self.node {
821 ast::MetaItemKind::Word => String::from(&*self.name.as_str()),
822 ast::MetaItemKind::List(ref list) => {
823 let name = self.name.as_str();
824 // 3 = `#[` and `(`, 2 = `]` and `)`
825 let item_shape = try_opt!(
827 .shrink_left(name.len() + 3)
828 .and_then(|s| s.sub_width(2))
830 let items = itemize_list(
834 |nested_meta_item| nested_meta_item.span.lo(),
835 |nested_meta_item| nested_meta_item.span.hi(),
836 |nested_meta_item| nested_meta_item.rewrite(context, item_shape),
841 let item_vec = items.collect::<Vec<_>>();
842 let fmt = ListFormatting {
843 tactic: DefinitiveListTactic::Mixed,
845 trailing_separator: SeparatorTactic::Never,
846 separator_place: SeparatorPlace::Back,
848 ends_with_newline: false,
849 preserve_newline: false,
850 config: context.config,
852 format!("{}({})", name, try_opt!(write_list(&item_vec, &fmt)))
854 ast::MetaItemKind::NameValue(ref literal) => {
855 let name = self.name.as_str();
856 let value = context.snippet(literal.span);
857 if &*name == "doc" && contains_comment(&value) {
858 let doc_shape = Shape {
859 width: cmp::min(shape.width, context.config.comment_width())
860 .checked_sub(shape.indent.width())
864 try_opt!(rewrite_comment(&value, false, doc_shape, context.config))
866 format!("{} = {}", name, value)
873 impl Rewrite for ast::Attribute {
874 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
875 try_opt!(self.meta())
876 .rewrite(context, shape)
877 .map(|rw| if self.is_sugared_doc {
880 let original = context.snippet(self.span);
881 let prefix = match self.style {
882 ast::AttrStyle::Inner => "#!",
883 ast::AttrStyle::Outer => "#",
885 if contains_comment(&original) {
888 format!("{}[{}]", prefix, rw)
894 impl<'a> Rewrite for [ast::Attribute] {
895 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
897 return Some(String::new());
899 let mut result = String::with_capacity(128);
900 let indent = shape.indent.to_string(context.config);
902 let mut derive_args = Vec::new();
904 let mut iter = self.iter().enumerate().peekable();
905 let mut insert_new_line = true;
906 let mut is_prev_sugared_doc = false;
907 while let Some((i, a)) = iter.next() {
908 let a_str = try_opt!(a.rewrite(context, shape));
910 // Write comments and blank lines between attributes.
912 let comment = context.snippet(mk_sp(self[i - 1].span.hi(), a.span.lo()));
913 // This particular horror show is to preserve line breaks in between doc
914 // comments. An alternative would be to force such line breaks to start
915 // with the usual doc comment token.
916 let (multi_line_before, multi_line_after) = if a.is_sugared_doc
917 || is_prev_sugared_doc
919 // Look at before and after comment and see if there are any empty lines.
920 let comment_begin = comment.chars().position(|c| c == '/');
921 let len = comment_begin.unwrap_or_else(|| comment.len());
922 let mlb = comment.chars().take(len).filter(|c| *c == '\n').count() > 1;
923 let mla = if comment_begin.is_none() {
926 let comment_end = comment.chars().rev().position(|c| !c.is_whitespace());
927 let len = comment_end.unwrap();
932 .filter(|c| *c == '\n')
940 let comment = try_opt!(recover_missing_comment_in_span(
941 mk_sp(self[i - 1].span.hi(), a.span.lo()),
942 shape.with_max_width(context.config),
947 if !comment.is_empty() {
948 if multi_line_before {
951 result.push_str(&comment);
953 if multi_line_after {
956 } else if insert_new_line {
958 if multi_line_after {
963 if derive_args.is_empty() {
964 result.push_str(&indent);
967 insert_new_line = true;
970 // Write the attribute itself.
971 if context.config.merge_derives() {
972 // If the attribute is `#[derive(...)]`, take the arguments.
973 if let Some(mut args) = get_derive_args(context, a) {
974 derive_args.append(&mut args);
976 // If the next attribute is `#[derive(...)]` as well, skip rewriting.
977 Some(&(_, next_attr)) if is_derive(next_attr) => insert_new_line = false,
978 // If not, rewrite the merged derives.
980 result.push_str(&try_opt!(format_derive(context, &derive_args, shape)));
985 result.push_str(&a_str);
988 result.push_str(&a_str);
991 is_prev_sugared_doc = a.is_sugared_doc;
997 // Format `#[derive(..)]`, using visual indent & mixed style when we need to go multiline.
998 fn format_derive(context: &RewriteContext, derive_args: &[String], shape: Shape) -> Option<String> {
999 let mut result = String::with_capacity(128);
1000 result.push_str("#[derive(");
1001 // 11 = `#[derive()]`
1002 let initial_budget = try_opt!(shape.width.checked_sub(11));
1003 let mut budget = initial_budget;
1004 let num = derive_args.len();
1005 for (i, a) in derive_args.iter().enumerate() {
1007 let width = a.len() + 2;
1010 // Remove trailing whitespace.
1015 result.push_str(&(shape.indent + 9).to_string(context.config));
1016 budget = initial_budget;
1018 budget = budget.checked_sub(width).unwrap_or(0);
1022 result.push_str(", ")
1025 result.push_str(")]");
1029 fn is_derive(attr: &ast::Attribute) -> bool {
1031 Some(meta_item) => match meta_item.node {
1032 ast::MetaItemKind::List(..) => meta_item.name.as_str() == "derive",
1039 /// Returns the arguments of `#[derive(...)]`.
1040 fn get_derive_args(context: &RewriteContext, attr: &ast::Attribute) -> Option<Vec<String>> {
1041 attr.meta().and_then(|meta_item| match meta_item.node {
1042 ast::MetaItemKind::List(ref args) if meta_item.name.as_str() == "derive" => {
1043 // Every argument of `derive` should be `NestedMetaItemKind::Literal`.
1046 .map(|a| context.snippet(a.span))
1047 .collect::<Vec<_>>(),
1054 // Rewrite `extern crate foo;` WITHOUT attributes.
1055 pub fn rewrite_extern_crate(context: &RewriteContext, item: &ast::Item) -> Option<String> {
1056 assert!(is_extern_crate(item));
1057 let new_str = context.snippet(item.span);
1058 Some(if contains_comment(&new_str) {
1061 let no_whitespace = &new_str.split_whitespace().collect::<Vec<&str>>().join(" ");
1062 String::from(&*Regex::new(r"\s;").unwrap().replace(no_whitespace, ";"))