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::codemap::{self, BytePos, CodeMap, Pos, Span};
  13 use syntax::parse::ParseSess;
  14 use syntax::{ast, visit};
  15
  16 use attr::*;
  17 use codemap::{LineRangeUtils, SpanUtils};
  18 use comment::{CodeCharKind, CommentCodeSlices, FindUncommented};
  19 use config::{BraceStyle, Config};
  20 use items::{
  21     format_impl, format_trait, format_trait_alias, is_mod_decl, is_use_item,
  22     rewrite_associated_impl_type, rewrite_associated_type, rewrite_existential_impl_type,
  23     rewrite_existential_type, rewrite_extern_crate, rewrite_type_alias, FnSig, StaticParts,
  24     StructParts,
  25 };
  26 use macros::{rewrite_macro, rewrite_macro_def, MacroPosition};
  27 use rewrite::{Rewrite, RewriteContext};
  28 use shape::{Indent, Shape};
  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 codemap: &'a CodeMap,
  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.codemap.lookup_char_pos(stmt.span.lo()),
  87             self.codemap.lookup_char_pos(stmt.span.hi())
  88         );
  89
  90         match stmt.node {
  91             ast::StmtKind::Item(ref item) => {
  92                 self.visit_item(item);
  93             }
  94             ast::StmtKind::Local(..) | ast::StmtKind::Expr(..) | ast::StmtKind::Semi(..) => {
  95                 if contains_skip(get_attrs_from_stmt(stmt)) {
  96                     self.push_skipped_with_span(stmt.span());
  97                 } else {
  98                     let rewrite = stmt.rewrite(&self.get_context(), self.shape());
  99                     self.push_rewrite(stmt.span(), rewrite)
 100                 }
 101             }
 102             ast::StmtKind::Mac(ref mac) => {
 103                 let (ref mac, _macro_style, ref attrs) = **mac;
 104                 if self.visit_attrs(attrs, ast::AttrStyle::Outer) {
 105                     self.push_skipped_with_span(stmt.span());
 106                 } else {
 107                     self.visit_mac(mac, None, MacroPosition::Statement);
 108                 }
 109                 self.format_missing(stmt.span.hi());
 110             }
 111         }
 112     }
 113
 114     pub fn visit_block(
 115         &mut self,
 116         b: &ast::Block,
 117         inner_attrs: Option<&[ast::Attribute]>,
 118         has_braces: bool,
 119     ) {
 120         debug!(
 121             "visit_block: {:?} {:?}",
 122             self.codemap.lookup_char_pos(b.span.lo()),
 123             self.codemap.lookup_char_pos(b.span.hi())
 124         );
 125
 126         // Check if this block has braces.
 127         let brace_compensation = BytePos(if has_braces { 1 } else { 0 });
 128
 129         self.last_pos = self.last_pos + brace_compensation;
 130         self.block_indent = self.block_indent.block_indent(self.config);
 131         self.push_str("{");
 132
 133         if let Some(first_stmt) = b.stmts.first() {
 134             let attr_lo = inner_attrs
 135                 .and_then(|attrs| inner_attributes(attrs).first().map(|attr| attr.span.lo()))
 136                 .or_else(|| {
 137                     // Attributes for an item in a statement position
 138                     // do not belong to the statement. (rust-lang/rust#34459)
 139                     if let ast::StmtKind::Item(ref item) = first_stmt.node {
 140                         item.attrs.first()
 141                     } else {
 142                         first_stmt.attrs().first()
 143                     }.and_then(|attr| {
 144                         // Some stmts can have embedded attributes.
 145                         // e.g. `match { #![attr] ... }`
 146                         let attr_lo = attr.span.lo();
 147                         if attr_lo < first_stmt.span.lo() {
 148                             Some(attr_lo)
 149                         } else {
 150                             None
 151                         }
 152                     })
 153                 });
 154
 155             let snippet = self.snippet(mk_sp(
 156                 self.last_pos,
 157                 attr_lo.unwrap_or_else(|| first_stmt.span.lo()),
 158             ));
 159             let len = CommentCodeSlices::new(snippet)
 160                 .nth(0)
 161                 .and_then(|(kind, _, s)| {
 162                     if kind == CodeCharKind::Normal {
 163                         s.rfind('\n')
 164                     } else {
 165                         None
 166                     }
 167                 });
 168             if let Some(len) = len {
 169                 self.last_pos = self.last_pos + BytePos::from_usize(len);
 170             }
 171         }
 172
 173         // Format inner attributes if available.
 174         let skip_rewrite = if let Some(attrs) = inner_attrs {
 175             self.visit_attrs(attrs, ast::AttrStyle::Inner)
 176         } else {
 177             false
 178         };
 179
 180         if skip_rewrite {
 181             self.push_rewrite(b.span, None);
 182             self.close_block(false);
 183             self.last_pos = source!(self, b.span).hi();
 184             return;
 185         }
 186
 187         self.walk_block_stmts(b);
 188
 189         if !b.stmts.is_empty() {
 190             if let Some(expr) = utils::stmt_expr(&b.stmts[b.stmts.len() - 1]) {
 191                 if utils::semicolon_for_expr(&self.get_context(), expr) {
 192                     self.push_str(";");
 193                 }
 194             }
 195         }
 196
 197         let mut remove_len = BytePos(0);
 198         if let Some(stmt) = b.stmts.last() {
 199             let snippet = self.snippet(mk_sp(
 200                 stmt.span.hi(),
 201                 source!(self, b.span).hi() - brace_compensation,
 202             ));
 203             let len = CommentCodeSlices::new(snippet)
 204                 .last()
 205                 .and_then(|(kind, _, s)| {
 206                     if kind == CodeCharKind::Normal && s.trim().is_empty() {
 207                         Some(s.len())
 208                     } else {
 209                         None
 210                     }
 211                 });
 212             if let Some(len) = len {
 213                 remove_len = BytePos::from_usize(len);
 214             }
 215         }
 216
 217         let unindent_comment = (self.is_if_else_block && !b.stmts.is_empty()) && {
 218             let end_pos = source!(self, b.span).hi() - brace_compensation - remove_len;
 219             let snippet = self.snippet(mk_sp(self.last_pos, end_pos));
 220             snippet.contains("//") || snippet.contains("/*")
 221         };
 222         // FIXME: we should compress any newlines here to just one
 223         if unindent_comment {
 224             self.block_indent = self.block_indent.block_unindent(self.config);
 225         }
 226         self.format_missing_with_indent(
 227             source!(self, b.span).hi() - brace_compensation - remove_len,
 228         );
 229         if unindent_comment {
 230             self.block_indent = self.block_indent.block_indent(self.config);
 231         }
 232         self.close_block(unindent_comment);
 233         self.last_pos = source!(self, b.span).hi();
 234     }
 235
 236     // FIXME: this is a terrible hack to indent the comments between the last
 237     // item in the block and the closing brace to the block's level.
 238     // The closing brace itself, however, should be indented at a shallower
 239     // level.
 240     fn close_block(&mut self, unindent_comment: bool) {
 241         let total_len = self.buffer.len();
 242         let chars_too_many = if unindent_comment {
 243             0
 244         } else if self.config.hard_tabs() {
 245             1
 246         } else {
 247             self.config.tab_spaces()
 248         };
 249         self.buffer.truncate(total_len - chars_too_many);
 250         self.push_str("}");
 251         self.block_indent = self.block_indent.block_unindent(self.config);
 252     }
 253
 254     // Note that this only gets called for function definitions. Required methods
 255     // on traits do not get handled here.
 256     // FIXME(topecongiro) Format async fn (#2812).
 257     fn visit_fn(
 258         &mut self,
 259         fk: visit::FnKind,
 260         generics: &ast::Generics,
 261         fd: &ast::FnDecl,
 262         s: Span,
 263         defaultness: ast::Defaultness,
 264         inner_attrs: Option<&[ast::Attribute]>,
 265     ) {
 266         let indent = self.block_indent;
 267         let block;
 268         let rewrite = match fk {
 269             visit::FnKind::ItemFn(ident, _, _, b) | visit::FnKind::Method(ident, _, _, b) => {
 270                 block = b;
 271                 self.rewrite_fn(
 272                     indent,
 273                     ident,
 274                     &FnSig::from_fn_kind(&fk, generics, fd, defaultness),
 275                     mk_sp(s.lo(), b.span.lo()),
 276                     b,
 277                     inner_attrs,
 278                 )
 279             }
 280             visit::FnKind::Closure(_) => unreachable!(),
 281         };
 282
 283         if let Some(fn_str) = rewrite {
 284             self.format_missing_with_indent(source!(self, s).lo());
 285             self.push_str(&fn_str);
 286             if let Some(c) = fn_str.chars().last() {
 287                 if c == '}' {
 288                     self.last_pos = source!(self, block.span).hi();
 289                     return;
 290                 }
 291             }
 292         } else {
 293             self.format_missing(source!(self, block.span).lo());
 294         }
 295
 296         self.last_pos = source!(self, block.span).lo();
 297         self.visit_block(block, inner_attrs, true)
 298     }
 299
 300     pub fn visit_item(&mut self, item: &ast::Item) {
 301         skip_out_of_file_lines_range_visitor!(self, item.span);
 302
 303         // This is where we bail out if there is a skip attribute. This is only
 304         // complex in the module case. It is complex because the module could be
 305         // in a separate file and there might be attributes in both files, but
 306         // the AST lumps them all together.
 307         let filtered_attrs;
 308         let mut attrs = &item.attrs;
 309         match item.node {
 310             // For use items, skip rewriting attributes. Just check for a skip attribute.
 311             ast::ItemKind::Use(..) => {
 312                 if contains_skip(attrs) {
 313                     self.push_skipped_with_span(item.span());
 314                     return;
 315                 }
 316             }
 317             // Module is inline, in this case we treat it like any other item.
 318             _ if !is_mod_decl(item) => {
 319                 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
 320                     self.push_skipped_with_span(item.span());
 321                     return;
 322                 }
 323             }
 324             // Module is not inline, but should be skipped.
 325             ast::ItemKind::Mod(..) if contains_skip(&item.attrs) => {
 326                 return;
 327             }
 328             // Module is not inline and should not be skipped. We want
 329             // to process only the attributes in the current file.
 330             ast::ItemKind::Mod(..) => {
 331                 filtered_attrs = filter_inline_attrs(&item.attrs, item.span());
 332                 // Assert because if we should skip it should be caught by
 333                 // the above case.
 334                 assert!(!self.visit_attrs(&filtered_attrs, ast::AttrStyle::Outer));
 335                 attrs = &filtered_attrs;
 336             }
 337             _ => {
 338                 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
 339                     self.push_skipped_with_span(item.span());
 340                     return;
 341                 }
 342             }
 343         }
 344
 345         match item.node {
 346             ast::ItemKind::Use(ref tree) => self.format_import(item, tree),
 347             ast::ItemKind::Impl(..) => {
 348                 let snippet = self.snippet(item.span);
 349                 let where_span_end = snippet
 350                     .find_uncommented("{")
 351                     .map(|x| BytePos(x as u32) + source!(self, item.span).lo());
 352                 let rw = format_impl(&self.get_context(), item, self.block_indent, where_span_end);
 353                 self.push_rewrite(item.span, rw);
 354             }
 355             ast::ItemKind::Trait(..) => {
 356                 let rw = format_trait(&self.get_context(), item, self.block_indent);
 357                 self.push_rewrite(item.span, rw);
 358             }
 359             ast::ItemKind::TraitAlias(ref generics, ref generic_bounds) => {
 360                 let shape = Shape::indented(self.block_indent, self.config);
 361                 let rw = format_trait_alias(
 362                     &self.get_context(),
 363                     item.ident,
 364                     generics,
 365                     generic_bounds,
 366                     shape,
 367                 );
 368                 self.push_rewrite(item.span, rw);
 369             }
 370             ast::ItemKind::ExternCrate(_) => {
 371                 let rw = rewrite_extern_crate(&self.get_context(), item);
 372                 self.push_rewrite(item.span, rw);
 373             }
 374             ast::ItemKind::Struct(..) | ast::ItemKind::Union(..) => {
 375                 self.visit_struct(&StructParts::from_item(item));
 376             }
 377             ast::ItemKind::Enum(ref def, ref generics) => {
 378                 self.format_missing_with_indent(source!(self, item.span).lo());
 379                 self.visit_enum(item.ident, &item.vis, def, generics, item.span);
 380                 self.last_pos = source!(self, item.span).hi();
 381             }
 382             ast::ItemKind::Mod(ref module) => {
 383                 let is_inline = !is_mod_decl(item);
 384                 self.format_missing_with_indent(source!(self, item.span).lo());
 385                 self.format_mod(module, &item.vis, item.span, item.ident, attrs, is_inline);
 386             }
 387             ast::ItemKind::Mac(ref mac) => {
 388                 self.visit_mac(mac, Some(item.ident), MacroPosition::Item);
 389             }
 390             ast::ItemKind::ForeignMod(ref foreign_mod) => {
 391                 self.format_missing_with_indent(source!(self, item.span).lo());
 392                 self.format_foreign_mod(foreign_mod, item.span);
 393             }
 394             ast::ItemKind::Static(..) | ast::ItemKind::Const(..) => {
 395                 self.visit_static(&StaticParts::from_item(item));
 396             }
 397             ast::ItemKind::Fn(ref decl, fn_header, ref generics, ref body) => {
 398                 let inner_attrs = inner_attributes(&item.attrs);
 399                 self.visit_fn(
 400                     visit::FnKind::ItemFn(item.ident, fn_header, &item.vis, body),
 401                     generics,
 402                     decl,
 403                     item.span,
 404                     ast::Defaultness::Final,
 405                     Some(&inner_attrs),
 406                 )
 407             }
 408             ast::ItemKind::Ty(ref ty, ref generics) => {
 409                 let rewrite = rewrite_type_alias(
 410                     &self.get_context(),
 411                     self.block_indent,
 412                     item.ident,
 413                     ty,
 414                     generics,
 415                     &item.vis,
 416                 );
 417                 self.push_rewrite(item.span, rewrite);
 418             }
 419             ast::ItemKind::Existential(ref generic_bounds, ref generics) => {
 420                 let rewrite = rewrite_existential_type(
 421                     &self.get_context(),
 422                     self.block_indent,
 423                     item.ident,
 424                     generic_bounds,
 425                     generics,
 426                     &item.vis,
 427                 );
 428                 self.push_rewrite(item.span, rewrite);
 429             }
 430             ast::ItemKind::GlobalAsm(..) => {
 431                 let snippet = Some(self.snippet(item.span).to_owned());
 432                 self.push_rewrite(item.span, snippet);
 433             }
 434             ast::ItemKind::MacroDef(ref def) => {
 435                 let rewrite = rewrite_macro_def(
 436                     &self.get_context(),
 437                     self.shape(),
 438                     self.block_indent,
 439                     def,
 440                     item.ident,
 441                     &item.vis,
 442                     item.span,
 443                 );
 444                 self.push_rewrite(item.span, rewrite);
 445             }
 446         }
 447     }
 448
 449     pub fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
 450         skip_out_of_file_lines_range_visitor!(self, ti.span);
 451
 452         if self.visit_attrs(&ti.attrs, ast::AttrStyle::Outer) {
 453             self.push_skipped_with_span(ti.span());
 454             return;
 455         }
 456
 457         match ti.node {
 458             ast::TraitItemKind::Const(..) => self.visit_static(&StaticParts::from_trait_item(ti)),
 459             ast::TraitItemKind::Method(ref sig, None) => {
 460                 let indent = self.block_indent;
 461                 let rewrite =
 462                     self.rewrite_required_fn(indent, ti.ident, sig, &ti.generics, ti.span);
 463                 self.push_rewrite(ti.span, rewrite);
 464             }
 465             ast::TraitItemKind::Method(ref sig, Some(ref body)) => {
 466                 let inner_attrs = inner_attributes(&ti.attrs);
 467                 self.visit_fn(
 468                     visit::FnKind::Method(ti.ident, sig, None, body),
 469                     &ti.generics,
 470                     &sig.decl,
 471                     ti.span,
 472                     ast::Defaultness::Final,
 473                     Some(&inner_attrs),
 474                 );
 475             }
 476             ast::TraitItemKind::Type(ref generic_bounds, ref type_default) => {
 477                 let rewrite = rewrite_associated_type(
 478                     ti.ident,
 479                     type_default.as_ref(),
 480                     Some(generic_bounds),
 481                     &self.get_context(),
 482                     self.block_indent,
 483                 );
 484                 self.push_rewrite(ti.span, rewrite);
 485             }
 486             ast::TraitItemKind::Macro(ref mac) => {
 487                 self.visit_mac(mac, Some(ti.ident), MacroPosition::Item);
 488             }
 489         }
 490     }
 491
 492     pub fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
 493         skip_out_of_file_lines_range_visitor!(self, ii.span);
 494
 495         if self.visit_attrs(&ii.attrs, ast::AttrStyle::Outer) {
 496             self.push_skipped_with_span(ii.span());
 497             return;
 498         }
 499
 500         match ii.node {
 501             ast::ImplItemKind::Method(ref sig, ref body) => {
 502                 let inner_attrs = inner_attributes(&ii.attrs);
 503                 self.visit_fn(
 504                     visit::FnKind::Method(ii.ident, sig, Some(&ii.vis), body),
 505                     &ii.generics,
 506                     &sig.decl,
 507                     ii.span,
 508                     ii.defaultness,
 509                     Some(&inner_attrs),
 510                 );
 511             }
 512             ast::ImplItemKind::Const(..) => self.visit_static(&StaticParts::from_impl_item(ii)),
 513             ast::ImplItemKind::Type(ref ty) => {
 514                 let rewrite = rewrite_associated_impl_type(
 515                     ii.ident,
 516                     ii.defaultness,
 517                     Some(ty),
 518                     &self.get_context(),
 519                     self.block_indent,
 520                 );
 521                 self.push_rewrite(ii.span, rewrite);
 522             }
 523             ast::ImplItemKind::Existential(ref generic_bounds) => {
 524                 let rewrite = rewrite_existential_impl_type(
 525                     &self.get_context(),
 526                     ii.ident,
 527                     generic_bounds,
 528                     self.block_indent,
 529                 );
 530                 self.push_rewrite(ii.span, rewrite);
 531             }
 532             ast::ImplItemKind::Macro(ref mac) => {
 533                 self.visit_mac(mac, Some(ii.ident), MacroPosition::Item);
 534             }
 535         }
 536     }
 537
 538     fn visit_mac(&mut self, mac: &ast::Mac, ident: Option<ast::Ident>, pos: MacroPosition) {
 539         skip_out_of_file_lines_range_visitor!(self, mac.span);
 540
 541         // 1 = ;
 542         let shape = self.shape().sub_width(1).unwrap();
 543         let rewrite = self.with_context(|ctx| rewrite_macro(mac, ident, ctx, shape, pos));
 544         self.push_rewrite(mac.span, rewrite);
 545     }
 546
 547     pub fn push_str(&mut self, s: &str) {
 548         self.line_number += count_newlines(s);
 549         self.buffer.push_str(s);
 550     }
 551
 552     #[cfg_attr(feature = "cargo-clippy", allow(needless_pass_by_value))]
 553     fn push_rewrite_inner(&mut self, span: Span, rewrite: Option<String>) {
 554         if let Some(ref s) = rewrite {
 555             self.push_str(s);
 556         } else {
 557             let snippet = self.snippet(span);
 558             self.push_str(snippet);
 559         }
 560         self.last_pos = source!(self, span).hi();
 561     }
 562
 563     pub fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
 564         self.format_missing_with_indent(source!(self, span).lo());
 565         self.push_rewrite_inner(span, rewrite);
 566     }
 567
 568     pub fn push_skipped_with_span(&mut self, span: Span) {
 569         self.format_missing_with_indent(source!(self, span).lo());
 570         let lo = self.line_number + 1;
 571         self.push_rewrite_inner(span, None);
 572         let hi = self.line_number + 1;
 573         self.skipped_range.push((lo, hi));
 574     }
 575
 576     pub fn from_context(ctx: &'a RewriteContext) -> FmtVisitor<'a> {
 577         FmtVisitor::from_codemap(
 578             ctx.parse_session,
 579             ctx.config,
 580             ctx.snippet_provider,
 581             ctx.report.clone(),
 582         )
 583     }
 584
 585     pub(crate) fn from_codemap(
 586         parse_session: &'a ParseSess,
 587         config: &'a Config,
 588         snippet_provider: &'a SnippetProvider,
 589         report: FormatReport,
 590     ) -> FmtVisitor<'a> {
 591         FmtVisitor {
 592             parse_session,
 593             codemap: parse_session.codemap(),
 594             buffer: String::with_capacity(snippet_provider.big_snippet.len() * 2),
 595             last_pos: BytePos(0),
 596             block_indent: Indent::empty(),
 597             config,
 598             is_if_else_block: false,
 599             snippet_provider,
 600             line_number: 0,
 601             skipped_range: vec![],
 602             macro_rewrite_failure: false,
 603             report,
 604         }
 605     }
 606
 607     pub fn opt_snippet(&'b self, span: Span) -> Option<&'a str> {
 608         self.snippet_provider.span_to_snippet(span)
 609     }
 610
 611     pub fn snippet(&'b self, span: Span) -> &'a str {
 612         self.opt_snippet(span).unwrap()
 613     }
 614
 615     // Returns true if we should skip the following item.
 616     pub fn visit_attrs(&mut self, attrs: &[ast::Attribute], style: ast::AttrStyle) -> bool {
 617         for attr in attrs {
 618             if attr.name() == DEPR_SKIP_ANNOTATION {
 619                 let file_name = self.codemap.span_to_filename(attr.span).into();
 620                 self.report.append(
 621                     file_name,
 622                     vec![FormattingError::from_span(
 623                         &attr.span,
 624                         &self.codemap,
 625                         ErrorKind::DeprecatedAttr,
 626                     )],
 627                 );
 628             } else if attr.path.segments[0].ident.to_string() == "rustfmt" {
 629                 if attr.path.segments.len() == 1
 630                     || attr.path.segments[1].ident.to_string() != "skip"
 631                 {
 632                     let file_name = self.codemap.span_to_filename(attr.span).into();
 633                     self.report.append(
 634                         file_name,
 635                         vec![FormattingError::from_span(
 636                             &attr.span,
 637                             &self.codemap,
 638                             ErrorKind::BadAttr,
 639                         )],
 640                     );
 641                 }
 642             }
 643         }
 644         if contains_skip(attrs) {
 645             return true;
 646         }
 647
 648         let attrs: Vec<_> = attrs.iter().filter(|a| a.style == style).cloned().collect();
 649         if attrs.is_empty() {
 650             return false;
 651         }
 652
 653         let rewrite = attrs.rewrite(&self.get_context(), self.shape());
 654         let span = mk_sp(attrs[0].span.lo(), attrs[attrs.len() - 1].span.hi());
 655         self.push_rewrite(span, rewrite);
 656
 657         false
 658     }
 659
 660     fn walk_mod_items(&mut self, m: &ast::Mod) {
 661         self.visit_items_with_reordering(&ptr_vec_to_ref_vec(&m.items));
 662     }
 663
 664     fn walk_stmts(&mut self, stmts: &[ast::Stmt]) {
 665         fn to_stmt_item(stmt: &ast::Stmt) -> Option<&ast::Item> {
 666             match stmt.node {
 667                 ast::StmtKind::Item(ref item) => Some(&**item),
 668                 _ => None,
 669             }
 670         }
 671
 672         if stmts.is_empty() {
 673             return;
 674         }
 675
 676         // Extract leading `use ...;`.
 677         let items: Vec<_> = stmts
 678             .iter()
 679             .take_while(|stmt| to_stmt_item(stmt).map_or(false, is_use_item))
 680             .filter_map(|stmt| to_stmt_item(stmt))
 681             .collect();
 682
 683         if items.is_empty() {
 684             self.visit_stmt(&stmts[0]);
 685             self.walk_stmts(&stmts[1..]);
 686         } else {
 687             self.visit_items_with_reordering(&items);
 688             self.walk_stmts(&stmts[items.len()..]);
 689         }
 690     }
 691
 692     fn walk_block_stmts(&mut self, b: &ast::Block) {
 693         self.walk_stmts(&b.stmts)
 694     }
 695
 696     fn format_mod(
 697         &mut self,
 698         m: &ast::Mod,
 699         vis: &ast::Visibility,
 700         s: Span,
 701         ident: ast::Ident,
 702         attrs: &[ast::Attribute],
 703         is_internal: bool,
 704     ) {
 705         let vis_str = utils::format_visibility(&self.get_context(), vis);
 706         self.push_str(&*vis_str);
 707         self.push_str("mod ");
 708         // Calling `to_owned()` to work around borrow checker.
 709         let ident_str = rewrite_ident(&self.get_context(), ident).to_owned();
 710         self.push_str(&ident_str);
 711
 712         if is_internal {
 713             match self.config.brace_style() {
 714                 BraceStyle::AlwaysNextLine => {
 715                     let indent_str = self.block_indent.to_string_with_newline(self.config);
 716                     self.push_str(&indent_str);
 717                     self.push_str("{");
 718                 }
 719                 _ => self.push_str(" {"),
 720             }
 721             // Hackery to account for the closing }.
 722             let mod_lo = self.snippet_provider.span_after(source!(self, s), "{");
 723             let body_snippet =
 724                 self.snippet(mk_sp(mod_lo, source!(self, m.inner).hi() - BytePos(1)));
 725             let body_snippet = body_snippet.trim();
 726             if body_snippet.is_empty() {
 727                 self.push_str("}");
 728             } else {
 729                 self.last_pos = mod_lo;
 730                 self.block_indent = self.block_indent.block_indent(self.config);
 731                 self.visit_attrs(attrs, ast::AttrStyle::Inner);
 732                 self.walk_mod_items(m);
 733                 self.format_missing_with_indent(source!(self, m.inner).hi() - BytePos(1));
 734                 self.close_block(false);
 735             }
 736             self.last_pos = source!(self, m.inner).hi();
 737         } else {
 738             self.push_str(";");
 739             self.last_pos = source!(self, s).hi();
 740         }
 741     }
 742
 743     pub fn format_separate_mod(&mut self, m: &ast::Mod, filemap: &codemap::FileMap) {
 744         self.block_indent = Indent::empty();
 745         self.walk_mod_items(m);
 746         self.format_missing_with_indent(filemap.end_pos);
 747     }
 748
 749     pub fn skip_empty_lines(&mut self, end_pos: BytePos) {
 750         while let Some(pos) = self
 751             .snippet_provider
 752             .opt_span_after(mk_sp(self.last_pos, end_pos), "\n")
 753         {
 754             if let Some(snippet) = self.opt_snippet(mk_sp(self.last_pos, pos)) {
 755                 if snippet.trim().is_empty() {
 756                     self.last_pos = pos;
 757                 } else {
 758                     return;
 759                 }
 760             }
 761         }
 762     }
 763
 764     pub fn with_context<F>(&mut self, f: F) -> Option<String>
 765     where
 766         F: Fn(&RewriteContext) -> Option<String>,
 767     {
 768         let result;
 769         let macro_rewrite_failure = {
 770             let context = self.get_context();
 771             result = f(&context);
 772             unsafe { *context.macro_rewrite_failure.as_ptr() }
 773         };
 774         self.macro_rewrite_failure |= macro_rewrite_failure;
 775         result
 776     }
 777
 778     pub fn get_context(&self) -> RewriteContext {
 779         RewriteContext {
 780             parse_session: self.parse_session,
 781             codemap: self.codemap,
 782             config: self.config,
 783             inside_macro: RefCell::new(false),
 784             use_block: RefCell::new(false),
 785             is_if_else_block: RefCell::new(false),
 786             force_one_line_chain: RefCell::new(false),
 787             snippet_provider: self.snippet_provider,
 788             macro_rewrite_failure: RefCell::new(false),
 789             report: self.report.clone(),
 790         }
 791     }
 792 }