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