src/visitor.rs

   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.
   4 //
   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.
  10
  11 use syntax::attr::HasAttrs;
  12 use syntax::parse::ParseSess;
  13 use syntax::source_map::{self, BytePos, Pos, SourceMap, Span};
  14 use syntax::{ast, visit};
  15
  16 use attr::*;
  17 use comment::{CodeCharKind, CommentCodeSlices, FindUncommented};
  18 use config::{BraceStyle, Config};
  19 use items::{
  20     format_impl, format_trait, format_trait_alias, is_mod_decl, is_use_item,
  21     rewrite_associated_impl_type, rewrite_associated_type, rewrite_existential_impl_type,
  22     rewrite_existential_type, rewrite_extern_crate, rewrite_type_alias, FnSig, StaticParts,
  23     StructParts,
  24 };
  25 use macros::{rewrite_macro, rewrite_macro_def, MacroPosition};
  26 use rewrite::{Rewrite, RewriteContext};
  27 use shape::{Indent, Shape};
  28 use source_map::{LineRangeUtils, SpanUtils};
  29 use spanned::Spanned;
  30 use utils::{
  31     self, contains_skip, count_newlines, inner_attributes, mk_sp, ptr_vec_to_ref_vec,
  32     rewrite_ident, DEPR_SKIP_ANNOTATION,
  33 };
  34 use {ErrorKind, FormatReport, FormattingError};
  35
  36 use std::cell::RefCell;
  37
  38 /// Creates a string slice corresponding to the specified span.
  39 pub struct SnippetProvider<'a> {
  40     /// A pointer to the content of the file we are formatting.
  41     big_snippet: &'a str,
  42     /// A position of the start of `big_snippet`, used as an offset.
  43     start_pos: usize,
  44 }
  45
  46 impl<'a> SnippetProvider<'a> {
  47     pub fn span_to_snippet(&self, span: Span) -> Option<&str> {
  48         let start_index = span.lo().to_usize().checked_sub(self.start_pos)?;
  49         let end_index = span.hi().to_usize().checked_sub(self.start_pos)?;
  50         Some(&self.big_snippet[start_index..end_index])
  51     }
  52
  53     pub fn new(start_pos: BytePos, big_snippet: &'a str) -> Self {
  54         let start_pos = start_pos.to_usize();
  55         SnippetProvider {
  56             big_snippet,
  57             start_pos,
  58         }
  59     }
  60 }
  61
  62 pub struct FmtVisitor<'a> {
  63     pub parse_session: &'a ParseSess,
  64     pub source_map: &'a SourceMap,
  65     pub buffer: String,
  66     pub last_pos: BytePos,
  67     // FIXME: use an RAII util or closure for indenting
  68     pub block_indent: Indent,
  69     pub config: &'a Config,
  70     pub is_if_else_block: bool,
  71     pub snippet_provider: &'a SnippetProvider<'a>,
  72     pub line_number: usize,
  73     pub skipped_range: Vec<(usize, usize)>,
  74     pub macro_rewrite_failure: bool,
  75     pub(crate) report: FormatReport,
  76 }
  77
  78 impl<'b, 'a: 'b> FmtVisitor<'a> {
  79     pub fn shape(&self) -> Shape {
  80         Shape::indented(self.block_indent, self.config)
  81     }
  82
  83     fn visit_stmt(&mut self, stmt: &ast::Stmt) {
  84         debug!(
  85             "visit_stmt: {:?} {:?}",
  86             self.source_map.lookup_char_pos(stmt.span.lo()),
  87             self.source_map.lookup_char_pos(stmt.span.hi())
  88         );
  89
  90         match stmt.node {
  91             ast::StmtKind::Item(ref item) => {
  92                 self.visit_item(item);
  93                 // Handle potential `;` after the item.
  94                 self.format_missing(stmt.span.hi());
  95             }
  96             ast::StmtKind::Local(..) | ast::StmtKind::Expr(..) | ast::StmtKind::Semi(..) => {
  97                 if contains_skip(get_attrs_from_stmt(stmt)) {
  98                     self.push_skipped_with_span(stmt.span());
  99                 } else {
 100                     let shape = self.shape().clone();
 101                     let rewrite = self.with_context(|ctx| stmt.rewrite(&ctx, shape));
 102                     self.push_rewrite(stmt.span(), rewrite)
 103                 }
 104             }
 105             ast::StmtKind::Mac(ref mac) => {
 106                 let (ref mac, _macro_style, ref attrs) = **mac;
 107                 if self.visit_attrs(attrs, ast::AttrStyle::Outer) {
 108                     self.push_skipped_with_span(stmt.span());
 109                 } else {
 110                     self.visit_mac(mac, None, MacroPosition::Statement);
 111                 }
 112                 self.format_missing(stmt.span.hi());
 113             }
 114         }
 115     }
 116
 117     pub fn visit_block(
 118         &mut self,
 119         b: &ast::Block,
 120         inner_attrs: Option<&[ast::Attribute]>,
 121         has_braces: bool,
 122     ) {
 123         debug!(
 124             "visit_block: {:?} {:?}",
 125             self.source_map.lookup_char_pos(b.span.lo()),
 126             self.source_map.lookup_char_pos(b.span.hi())
 127         );
 128
 129         // Check if this block has braces.
 130         let brace_compensation = BytePos(if has_braces { 1 } else { 0 });
 131
 132         self.last_pos = self.last_pos + brace_compensation;
 133         self.block_indent = self.block_indent.block_indent(self.config);
 134         self.push_str("{");
 135
 136         if let Some(first_stmt) = b.stmts.first() {
 137             let attr_lo = inner_attrs
 138                 .and_then(|attrs| inner_attributes(attrs).first().map(|attr| attr.span.lo()))
 139                 .or_else(|| {
 140                     // Attributes for an item in a statement position
 141                     // do not belong to the statement. (rust-lang/rust#34459)
 142                     if let ast::StmtKind::Item(ref item) = first_stmt.node {
 143                         item.attrs.first()
 144                     } else {
 145                         first_stmt.attrs().first()
 146                     }.and_then(|attr| {
 147                         // Some stmts can have embedded attributes.
 148                         // e.g. `match { #![attr] ... }`
 149                         let attr_lo = attr.span.lo();
 150                         if attr_lo < first_stmt.span.lo() {
 151                             Some(attr_lo)
 152                         } else {
 153                             None
 154                         }
 155                     })
 156                 });
 157
 158             let snippet = self.snippet(mk_sp(
 159                 self.last_pos,
 160                 attr_lo.unwrap_or_else(|| first_stmt.span.lo()),
 161             ));
 162             let len = CommentCodeSlices::new(snippet)
 163                 .nth(0)
 164                 .and_then(|(kind, _, s)| {
 165                     if kind == CodeCharKind::Normal {
 166                         s.rfind('\n')
 167                     } else {
 168                         None
 169                     }
 170                 });
 171             if let Some(len) = len {
 172                 self.last_pos = self.last_pos + BytePos::from_usize(len);
 173             }
 174         }
 175
 176         // Format inner attributes if available.
 177         let skip_rewrite = if let Some(attrs) = inner_attrs {
 178             self.visit_attrs(attrs, ast::AttrStyle::Inner)
 179         } else {
 180             false
 181         };
 182
 183         if skip_rewrite {
 184             self.push_rewrite(b.span, None);
 185             self.close_block(false);
 186             self.last_pos = source!(self, b.span).hi();
 187             return;
 188         }
 189
 190         self.walk_block_stmts(b);
 191
 192         if !b.stmts.is_empty() {
 193             if let Some(expr) = utils::stmt_expr(&b.stmts[b.stmts.len() - 1]) {
 194                 if utils::semicolon_for_expr(&self.get_context(), expr) {
 195                     self.push_str(";");
 196                 }
 197             }
 198         }
 199
 200         let mut remove_len = BytePos(0);
 201         if let Some(stmt) = b.stmts.last() {
 202             let snippet = self.snippet(mk_sp(
 203                 stmt.span.hi(),
 204                 source!(self, b.span).hi() - brace_compensation,
 205             ));
 206             let len = CommentCodeSlices::new(snippet)
 207                 .last()
 208                 .and_then(|(kind, _, s)| {
 209                     if kind == CodeCharKind::Normal && s.trim().is_empty() {
 210                         Some(s.len())
 211                     } else {
 212                         None
 213                     }
 214                 });
 215             if let Some(len) = len {
 216                 remove_len = BytePos::from_usize(len);
 217             }
 218         }
 219
 220         let unindent_comment = (self.is_if_else_block && !b.stmts.is_empty()) && {
 221             let end_pos = source!(self, b.span).hi() - brace_compensation - remove_len;
 222             let snippet = self.snippet(mk_sp(self.last_pos, end_pos));
 223             snippet.contains("//") || snippet.contains("/*")
 224         };
 225         // FIXME: we should compress any newlines here to just one
 226         if unindent_comment {
 227             self.block_indent = self.block_indent.block_unindent(self.config);
 228         }
 229         self.format_missing_with_indent(
 230             source!(self, b.span).hi() - brace_compensation - remove_len,
 231         );
 232         if unindent_comment {
 233             self.block_indent = self.block_indent.block_indent(self.config);
 234         }
 235         self.close_block(unindent_comment);
 236         self.last_pos = source!(self, b.span).hi();
 237     }
 238
 239     // FIXME: this is a terrible hack to indent the comments between the last
 240     // item in the block and the closing brace to the block's level.
 241     // The closing brace itself, however, should be indented at a shallower
 242     // level.
 243     fn close_block(&mut self, unindent_comment: bool) {
 244         let total_len = self.buffer.len();
 245         let chars_too_many = if unindent_comment {
 246             0
 247         } else if self.config.hard_tabs() {
 248             1
 249         } else {
 250             self.config.tab_spaces()
 251         };
 252         self.buffer.truncate(total_len - chars_too_many);
 253         self.push_str("}");
 254         self.block_indent = self.block_indent.block_unindent(self.config);
 255     }
 256
 257     // Note that this only gets called for function definitions. Required methods
 258     // on traits do not get handled here.
 259     fn visit_fn(
 260         &mut self,
 261         fk: visit::FnKind,
 262         generics: &ast::Generics,
 263         fd: &ast::FnDecl,
 264         s: Span,
 265         defaultness: ast::Defaultness,
 266         inner_attrs: Option<&[ast::Attribute]>,
 267     ) {
 268         let indent = self.block_indent;
 269         let block;
 270         let rewrite = match fk {
 271             visit::FnKind::ItemFn(ident, _, _, b) | visit::FnKind::Method(ident, _, _, b) => {
 272                 block = b;
 273                 self.rewrite_fn(
 274                     indent,
 275                     ident,
 276                     &FnSig::from_fn_kind(&fk, generics, fd, defaultness),
 277                     mk_sp(s.lo(), b.span.lo()),
 278                     b,
 279                     inner_attrs,
 280                 )
 281             }
 282             visit::FnKind::Closure(_) => unreachable!(),
 283         };
 284
 285         if let Some(fn_str) = rewrite {
 286             self.format_missing_with_indent(source!(self, s).lo());
 287             self.push_str(&fn_str);
 288             if let Some(c) = fn_str.chars().last() {
 289                 if c == '}' {
 290                     self.last_pos = source!(self, block.span).hi();
 291                     return;
 292                 }
 293             }
 294         } else {
 295             self.format_missing(source!(self, block.span).lo());
 296         }
 297
 298         self.last_pos = source!(self, block.span).lo();
 299         self.visit_block(block, inner_attrs, true)
 300     }
 301
 302     pub fn visit_item(&mut self, item: &ast::Item) {
 303         skip_out_of_file_lines_range_visitor!(self, item.span);
 304
 305         // This is where we bail out if there is a skip attribute. This is only
 306         // complex in the module case. It is complex because the module could be
 307         // in a separate file and there might be attributes in both files, but
 308         // the AST lumps them all together.
 309         let filtered_attrs;
 310         let mut attrs = &item.attrs;
 311         match item.node {
 312             // For use items, skip rewriting attributes. Just check for a skip attribute.
 313             ast::ItemKind::Use(..) => {
 314                 if contains_skip(attrs) {
 315                     self.push_skipped_with_span(item.span());
 316                     return;
 317                 }
 318             }
 319             // Module is inline, in this case we treat it like any other item.
 320             _ if !is_mod_decl(item) => {
 321                 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
 322                     self.push_skipped_with_span(item.span());
 323                     return;
 324                 }
 325             }
 326             // Module is not inline, but should be skipped.
 327             ast::ItemKind::Mod(..) if contains_skip(&item.attrs) => {
 328                 return;
 329             }
 330             // Module is not inline and should not be skipped. We want
 331             // to process only the attributes in the current file.
 332             ast::ItemKind::Mod(..) => {
 333                 filtered_attrs = filter_inline_attrs(&item.attrs, item.span());
 334                 // Assert because if we should skip it should be caught by
 335                 // the above case.
 336                 assert!(!self.visit_attrs(&filtered_attrs, ast::AttrStyle::Outer));
 337                 attrs = &filtered_attrs;
 338             }
 339             _ => {
 340                 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
 341                     self.push_skipped_with_span(item.span());
 342                     return;
 343                 }
 344             }
 345         }
 346
 347         match item.node {
 348             ast::ItemKind::Use(ref tree) => self.format_import(item, tree),
 349             ast::ItemKind::Impl(..) => {
 350                 let snippet = self.snippet(item.span);
 351                 let where_span_end = snippet
 352                     .find_uncommented("{")
 353                     .map(|x| BytePos(x as u32) + source!(self, item.span).lo());
 354                 let block_indent = self.block_indent.clone();
 355                 let rw =
 356                     self.with_context(|ctx| format_impl(&ctx, item, block_indent, where_span_end));
 357                 self.push_rewrite(item.span, rw);
 358             }
 359             ast::ItemKind::Trait(..) => {
 360                 let block_indent = self.block_indent.clone();
 361                 let rw = self.with_context(|ctx| format_trait(&ctx, item, block_indent));
 362                 self.push_rewrite(item.span, rw);
 363             }
 364             ast::ItemKind::TraitAlias(ref generics, ref generic_bounds) => {
 365                 let shape = Shape::indented(self.block_indent, self.config);
 366                 let rw = format_trait_alias(
 367                     &self.get_context(),
 368                     item.ident,
 369                     generics,
 370                     generic_bounds,
 371                     shape,
 372                 );
 373                 self.push_rewrite(item.span, rw);
 374             }
 375             ast::ItemKind::ExternCrate(_) => {
 376                 let rw = rewrite_extern_crate(&self.get_context(), item);
 377                 self.push_rewrite(item.span, rw);
 378             }
 379             ast::ItemKind::Struct(..) | ast::ItemKind::Union(..) => {
 380                 self.visit_struct(&StructParts::from_item(item));
 381             }
 382             ast::ItemKind::Enum(ref def, ref generics) => {
 383                 self.format_missing_with_indent(source!(self, item.span).lo());
 384                 self.visit_enum(item.ident, &item.vis, def, generics, item.span);
 385                 self.last_pos = source!(self, item.span).hi();
 386             }
 387             ast::ItemKind::Mod(ref module) => {
 388                 let is_inline = !is_mod_decl(item);
 389                 self.format_missing_with_indent(source!(self, item.span).lo());
 390                 self.format_mod(module, &item.vis, item.span, item.ident, attrs, is_inline);
 391             }
 392             ast::ItemKind::Mac(ref mac) => {
 393                 self.visit_mac(mac, Some(item.ident), MacroPosition::Item);
 394             }
 395             ast::ItemKind::ForeignMod(ref foreign_mod) => {
 396                 self.format_missing_with_indent(source!(self, item.span).lo());
 397                 self.format_foreign_mod(foreign_mod, item.span);
 398             }
 399             ast::ItemKind::Static(..) | ast::ItemKind::Const(..) => {
 400                 self.visit_static(&StaticParts::from_item(item));
 401             }
 402             ast::ItemKind::Fn(ref decl, fn_header, ref generics, ref body) => {
 403                 let inner_attrs = inner_attributes(&item.attrs);
 404                 self.visit_fn(
 405                     visit::FnKind::ItemFn(item.ident, fn_header, &item.vis, body),
 406                     generics,
 407                     decl,
 408                     item.span,
 409                     ast::Defaultness::Final,
 410                     Some(&inner_attrs),
 411                 )
 412             }
 413             ast::ItemKind::Ty(ref ty, ref generics) => {
 414                 let rewrite = rewrite_type_alias(
 415                     &self.get_context(),
 416                     self.block_indent,
 417                     item.ident,
 418                     ty,
 419                     generics,
 420                     &item.vis,
 421                 );
 422                 self.push_rewrite(item.span, rewrite);
 423             }
 424             ast::ItemKind::Existential(ref generic_bounds, ref generics) => {
 425                 let rewrite = rewrite_existential_type(
 426                     &self.get_context(),
 427                     self.block_indent,
 428                     item.ident,
 429                     generic_bounds,
 430                     generics,
 431                     &item.vis,
 432                 );
 433                 self.push_rewrite(item.span, rewrite);
 434             }
 435             ast::ItemKind::GlobalAsm(..) => {
 436                 let snippet = Some(self.snippet(item.span).to_owned());
 437                 self.push_rewrite(item.span, snippet);
 438             }
 439             ast::ItemKind::MacroDef(ref def) => {
 440                 let rewrite = rewrite_macro_def(
 441                     &self.get_context(),
 442                     self.shape(),
 443                     self.block_indent,
 444                     def,
 445                     item.ident,
 446                     &item.vis,
 447                     item.span,
 448                 );
 449                 self.push_rewrite(item.span, rewrite);
 450             }
 451         }
 452     }
 453
 454     pub fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
 455         skip_out_of_file_lines_range_visitor!(self, ti.span);
 456
 457         if self.visit_attrs(&ti.attrs, ast::AttrStyle::Outer) {
 458             self.push_skipped_with_span(ti.span());
 459             return;
 460         }
 461
 462         match ti.node {
 463             ast::TraitItemKind::Const(..) => self.visit_static(&StaticParts::from_trait_item(ti)),
 464             ast::TraitItemKind::Method(ref sig, None) => {
 465                 let indent = self.block_indent;
 466                 let rewrite =
 467                     self.rewrite_required_fn(indent, ti.ident, sig, &ti.generics, ti.span);
 468                 self.push_rewrite(ti.span, rewrite);
 469             }
 470             ast::TraitItemKind::Method(ref sig, Some(ref body)) => {
 471                 let inner_attrs = inner_attributes(&ti.attrs);
 472                 self.visit_fn(
 473                     visit::FnKind::Method(ti.ident, sig, None, body),
 474                     &ti.generics,
 475                     &sig.decl,
 476                     ti.span,
 477                     ast::Defaultness::Final,
 478                     Some(&inner_attrs),
 479                 );
 480             }
 481             ast::TraitItemKind::Type(ref generic_bounds, ref type_default) => {
 482                 let rewrite = rewrite_associated_type(
 483                     ti.ident,
 484                     type_default.as_ref(),
 485                     Some(generic_bounds),
 486                     &self.get_context(),
 487                     self.block_indent,
 488                 );
 489                 self.push_rewrite(ti.span, rewrite);
 490             }
 491             ast::TraitItemKind::Macro(ref mac) => {
 492                 self.visit_mac(mac, Some(ti.ident), MacroPosition::Item);
 493             }
 494         }
 495     }
 496
 497     pub fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
 498         skip_out_of_file_lines_range_visitor!(self, ii.span);
 499
 500         if self.visit_attrs(&ii.attrs, ast::AttrStyle::Outer) {
 501             self.push_skipped_with_span(ii.span());
 502             return;
 503         }
 504
 505         match ii.node {
 506             ast::ImplItemKind::Method(ref sig, ref body) => {
 507                 let inner_attrs = inner_attributes(&ii.attrs);
 508                 self.visit_fn(
 509                     visit::FnKind::Method(ii.ident, sig, Some(&ii.vis), body),
 510                     &ii.generics,
 511                     &sig.decl,
 512                     ii.span,
 513                     ii.defaultness,
 514                     Some(&inner_attrs),
 515                 );
 516             }
 517             ast::ImplItemKind::Const(..) => self.visit_static(&StaticParts::from_impl_item(ii)),
 518             ast::ImplItemKind::Type(ref ty) => {
 519                 let rewrite = rewrite_associated_impl_type(
 520                     ii.ident,
 521                     ii.defaultness,
 522                     Some(ty),
 523                     &self.get_context(),
 524                     self.block_indent,
 525                 );
 526                 self.push_rewrite(ii.span, rewrite);
 527             }
 528             ast::ImplItemKind::Existential(ref generic_bounds) => {
 529                 let rewrite = rewrite_existential_impl_type(
 530                     &self.get_context(),
 531                     ii.ident,
 532                     generic_bounds,
 533                     self.block_indent,
 534                 );
 535                 self.push_rewrite(ii.span, rewrite);
 536             }
 537             ast::ImplItemKind::Macro(ref mac) => {
 538                 self.visit_mac(mac, Some(ii.ident), MacroPosition::Item);
 539             }
 540         }
 541     }
 542
 543     fn visit_mac(&mut self, mac: &ast::Mac, ident: Option<ast::Ident>, pos: MacroPosition) {
 544         skip_out_of_file_lines_range_visitor!(self, mac.span);
 545
 546         // 1 = ;
 547         let shape = self.shape().sub_width(1).unwrap();
 548         let rewrite = self.with_context(|ctx| rewrite_macro(mac, ident, ctx, shape, pos));
 549         self.push_rewrite(mac.span, rewrite);
 550     }
 551
 552     pub fn push_str(&mut self, s: &str) {
 553         self.line_number += count_newlines(s);
 554         self.buffer.push_str(s);
 555     }
 556
 557     #[cfg_attr(feature = "cargo-clippy", allow(needless_pass_by_value))]
 558     fn push_rewrite_inner(&mut self, span: Span, rewrite: Option<String>) {
 559         if let Some(ref s) = rewrite {
 560             self.push_str(s);
 561         } else {
 562             let snippet = self.snippet(span);
 563             self.push_str(snippet);
 564         }
 565         self.last_pos = source!(self, span).hi();
 566     }
 567
 568     pub fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
 569         self.format_missing_with_indent(source!(self, span).lo());
 570         self.push_rewrite_inner(span, rewrite);
 571     }
 572
 573     pub fn push_skipped_with_span(&mut self, span: Span) {
 574         self.format_missing_with_indent(source!(self, span).lo());
 575         let lo = self.line_number + 1;
 576         self.push_rewrite_inner(span, None);
 577         let hi = self.line_number + 1;
 578         self.skipped_range.push((lo, hi));
 579     }
 580
 581     pub fn from_context(ctx: &'a RewriteContext) -> FmtVisitor<'a> {
 582         FmtVisitor::from_source_map(
 583             ctx.parse_session,
 584             ctx.config,
 585             ctx.snippet_provider,
 586             ctx.report.clone(),
 587         )
 588     }
 589
 590     pub(crate) fn from_source_map(
 591         parse_session: &'a ParseSess,
 592         config: &'a Config,
 593         snippet_provider: &'a SnippetProvider,
 594         report: FormatReport,
 595     ) -> FmtVisitor<'a> {
 596         FmtVisitor {
 597             parse_session,
 598             source_map: parse_session.source_map(),
 599             buffer: String::with_capacity(snippet_provider.big_snippet.len() * 2),
 600             last_pos: BytePos(0),
 601             block_indent: Indent::empty(),
 602             config,
 603             is_if_else_block: false,
 604             snippet_provider,
 605             line_number: 0,
 606             skipped_range: vec![],
 607             macro_rewrite_failure: false,
 608             report,
 609         }
 610     }
 611
 612     pub fn opt_snippet(&'b self, span: Span) -> Option<&'a str> {
 613         self.snippet_provider.span_to_snippet(span)
 614     }
 615
 616     pub fn snippet(&'b self, span: Span) -> &'a str {
 617         self.opt_snippet(span).unwrap()
 618     }
 619
 620     // Returns true if we should skip the following item.
 621     pub fn visit_attrs(&mut self, attrs: &[ast::Attribute], style: ast::AttrStyle) -> bool {
 622         for attr in attrs {
 623             if attr.name() == DEPR_SKIP_ANNOTATION {
 624                 let file_name = self.source_map.span_to_filename(attr.span).into();
 625                 self.report.append(
 626                     file_name,
 627                     vec![FormattingError::from_span(
 628                         attr.span,
 629                         &self.source_map,
 630                         ErrorKind::DeprecatedAttr,
 631                     )],
 632                 );
 633             } else if attr.path.segments[0].ident.to_string() == "rustfmt" {
 634                 if attr.path.segments.len() == 1
 635                     || attr.path.segments[1].ident.to_string() != "skip"
 636                 {
 637                     let file_name = self.source_map.span_to_filename(attr.span).into();
 638                     self.report.append(
 639                         file_name,
 640                         vec![FormattingError::from_span(
 641                             attr.span,
 642                             &self.source_map,
 643                             ErrorKind::BadAttr,
 644                         )],
 645                     );
 646                 }
 647             }
 648         }
 649         if contains_skip(attrs) {
 650             return true;
 651         }
 652
 653         let attrs: Vec<_> = attrs.iter().filter(|a| a.style == style).cloned().collect();
 654         if attrs.is_empty() {
 655             return false;
 656         }
 657
 658         let rewrite = attrs.rewrite(&self.get_context(), self.shape());
 659         let span = mk_sp(attrs[0].span.lo(), attrs[attrs.len() - 1].span.hi());
 660         self.push_rewrite(span, rewrite);
 661
 662         false
 663     }
 664
 665     fn walk_mod_items(&mut self, m: &ast::Mod) {
 666         self.visit_items_with_reordering(&ptr_vec_to_ref_vec(&m.items));
 667     }
 668
 669     fn walk_stmts(&mut self, stmts: &[ast::Stmt]) {
 670         fn to_stmt_item(stmt: &ast::Stmt) -> Option<&ast::Item> {
 671             match stmt.node {
 672                 ast::StmtKind::Item(ref item) => Some(&**item),
 673                 _ => None,
 674             }
 675         }
 676
 677         if stmts.is_empty() {
 678             return;
 679         }
 680
 681         // Extract leading `use ...;`.
 682         let items: Vec<_> = stmts
 683             .iter()
 684             .take_while(|stmt| to_stmt_item(stmt).map_or(false, is_use_item))
 685             .filter_map(|stmt| to_stmt_item(stmt))
 686             .collect();
 687
 688         if items.is_empty() {
 689             self.visit_stmt(&stmts[0]);
 690             self.walk_stmts(&stmts[1..]);
 691         } else {
 692             self.visit_items_with_reordering(&items);
 693             self.walk_stmts(&stmts[items.len()..]);
 694         }
 695     }
 696
 697     fn walk_block_stmts(&mut self, b: &ast::Block) {
 698         self.walk_stmts(&b.stmts)
 699     }
 700
 701     fn format_mod(
 702         &mut self,
 703         m: &ast::Mod,
 704         vis: &ast::Visibility,
 705         s: Span,
 706         ident: ast::Ident,
 707         attrs: &[ast::Attribute],
 708         is_internal: bool,
 709     ) {
 710         let vis_str = utils::format_visibility(&self.get_context(), vis);
 711         self.push_str(&*vis_str);
 712         self.push_str("mod ");
 713         // Calling `to_owned()` to work around borrow checker.
 714         let ident_str = rewrite_ident(&self.get_context(), ident).to_owned();
 715         self.push_str(&ident_str);
 716
 717         if is_internal {
 718             match self.config.brace_style() {
 719                 BraceStyle::AlwaysNextLine => {
 720                     let indent_str = self.block_indent.to_string_with_newline(self.config);
 721                     self.push_str(&indent_str);
 722                     self.push_str("{");
 723                 }
 724                 _ => self.push_str(" {"),
 725             }
 726             // Hackery to account for the closing }.
 727             let mod_lo = self.snippet_provider.span_after(source!(self, s), "{");
 728             let body_snippet =
 729                 self.snippet(mk_sp(mod_lo, source!(self, m.inner).hi() - BytePos(1)));
 730             let body_snippet = body_snippet.trim();
 731             if body_snippet.is_empty() {
 732                 self.push_str("}");
 733             } else {
 734                 self.last_pos = mod_lo;
 735                 self.block_indent = self.block_indent.block_indent(self.config);
 736                 self.visit_attrs(attrs, ast::AttrStyle::Inner);
 737                 self.walk_mod_items(m);
 738                 self.format_missing_with_indent(source!(self, m.inner).hi() - BytePos(1));
 739                 self.close_block(false);
 740             }
 741             self.last_pos = source!(self, m.inner).hi();
 742         } else {
 743             self.push_str(";");
 744             self.last_pos = source!(self, s).hi();
 745         }
 746     }
 747
 748     pub fn format_separate_mod(&mut self, m: &ast::Mod, source_file: &source_map::SourceFile) {
 749         self.block_indent = Indent::empty();
 750         self.walk_mod_items(m);
 751         self.format_missing_with_indent(source_file.end_pos);
 752     }
 753
 754     pub fn skip_empty_lines(&mut self, end_pos: BytePos) {
 755         while let Some(pos) = self
 756             .snippet_provider
 757             .opt_span_after(mk_sp(self.last_pos, end_pos), "\n")
 758         {
 759             if let Some(snippet) = self.opt_snippet(mk_sp(self.last_pos, pos)) {
 760                 if snippet.trim().is_empty() {
 761                     self.last_pos = pos;
 762                 } else {
 763                     return;
 764                 }
 765             }
 766         }
 767     }
 768
 769     pub fn with_context<F>(&mut self, f: F) -> Option<String>
 770     where
 771         F: Fn(&RewriteContext) -> Option<String>,
 772     {
 773         let result;
 774         let macro_rewrite_failure = {
 775             let context = self.get_context();
 776             result = f(&context);
 777             unsafe { *context.macro_rewrite_failure.as_ptr() }
 778         };
 779         self.macro_rewrite_failure |= macro_rewrite_failure;
 780         result
 781     }
 782
 783     pub fn get_context(&self) -> RewriteContext {
 784         RewriteContext {
 785             parse_session: self.parse_session,
 786             source_map: self.source_map,
 787             config: self.config,
 788             inside_macro: RefCell::new(false),
 789             use_block: RefCell::new(false),
 790             is_if_else_block: RefCell::new(false),
 791             force_one_line_chain: RefCell::new(false),
 792             snippet_provider: self.snippet_provider,
 793             macro_rewrite_failure: RefCell::new(false),
 794             report: self.report.clone(),
 795         }
 796     }
 797 }