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