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     rewrite_ident, 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 macro_rewrite_failure: bool,
  74     pub(crate) report: FormatReport,
  75 }
  76
  77 impl<'b, 'a: 'b> FmtVisitor<'a> {
  78     pub fn shape(&self) -> Shape {
  79         Shape::indented(self.block_indent, self.config)
  80     }
  81
  82     fn visit_stmt(&mut self, stmt: &ast::Stmt) {
  83         debug!(
  84             "visit_stmt: {:?} {:?}",
  85             self.codemap.lookup_char_pos(stmt.span.lo()),
  86             self.codemap.lookup_char_pos(stmt.span.hi())
  87         );
  88
  89         match stmt.node {
  90             ast::StmtKind::Item(ref item) => {
  91                 self.visit_item(item);
  92             }
  93             ast::StmtKind::Local(..) | ast::StmtKind::Expr(..) | ast::StmtKind::Semi(..) => {
  94                 if contains_skip(get_attrs_from_stmt(stmt)) {
  95                     self.push_skipped_with_span(stmt.span());
  96                 } else {
  97                     let rewrite = stmt.rewrite(&self.get_context(), self.shape());
  98                     self.push_rewrite(stmt.span(), rewrite)
  99                 }
 100             }
 101             ast::StmtKind::Mac(ref mac) => {
 102                 let (ref mac, _macro_style, ref attrs) = **mac;
 103                 if self.visit_attrs(attrs, ast::AttrStyle::Outer) {
 104                     self.push_skipped_with_span(stmt.span());
 105                 } else {
 106                     self.visit_mac(mac, None, MacroPosition::Statement);
 107                 }
 108                 self.format_missing(stmt.span.hi());
 109             }
 110         }
 111     }
 112
 113     pub fn visit_block(
 114         &mut self,
 115         b: &ast::Block,
 116         inner_attrs: Option<&[ast::Attribute]>,
 117         has_braces: bool,
 118     ) {
 119         debug!(
 120             "visit_block: {:?} {:?}",
 121             self.codemap.lookup_char_pos(b.span.lo()),
 122             self.codemap.lookup_char_pos(b.span.hi())
 123         );
 124
 125         // Check if this block has braces.
 126         let brace_compensation = BytePos(if has_braces { 1 } else { 0 });
 127
 128         self.last_pos = self.last_pos + brace_compensation;
 129         self.block_indent = self.block_indent.block_indent(self.config);
 130         self.push_str("{");
 131
 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         // Format inner attributes if available.
 173         let skip_rewrite = if let Some(attrs) = inner_attrs {
 174             self.visit_attrs(attrs, ast::AttrStyle::Inner)
 175         } else {
 176             false
 177         };
 178
 179         if skip_rewrite {
 180             self.push_rewrite(b.span, None);
 181             self.close_block(false);
 182             self.last_pos = source!(self, b.span).hi();
 183             return;
 184         }
 185
 186         self.walk_block_stmts(b);
 187
 188         if !b.stmts.is_empty() {
 189             if let Some(expr) = utils::stmt_expr(&b.stmts[b.stmts.len() - 1]) {
 190                 if utils::semicolon_for_expr(&self.get_context(), expr) {
 191                     self.push_str(";");
 192                 }
 193             }
 194         }
 195
 196         let mut remove_len = BytePos(0);
 197         if let Some(stmt) = b.stmts.last() {
 198             let snippet = self.snippet(mk_sp(
 199                 stmt.span.hi(),
 200                 source!(self, b.span).hi() - brace_compensation,
 201             ));
 202             let len = CommentCodeSlices::new(snippet)
 203                 .last()
 204                 .and_then(|(kind, _, s)| {
 205                     if kind == CodeCharKind::Normal && s.trim().is_empty() {
 206                         Some(s.len())
 207                     } else {
 208                         None
 209                     }
 210                 });
 211             if let Some(len) = len {
 212                 remove_len = BytePos::from_usize(len);
 213             }
 214         }
 215
 216         let unindent_comment = (self.is_if_else_block && !b.stmts.is_empty()) && {
 217             let end_pos = source!(self, b.span).hi() - brace_compensation - remove_len;
 218             let snippet = self.snippet(mk_sp(self.last_pos, end_pos));
 219             snippet.contains("//") || snippet.contains("/*")
 220         };
 221         // FIXME: we should compress any newlines here to just one
 222         if unindent_comment {
 223             self.block_indent = self.block_indent.block_unindent(self.config);
 224         }
 225         self.format_missing_with_indent(
 226             source!(self, b.span).hi() - brace_compensation - remove_len,
 227         );
 228         if unindent_comment {
 229             self.block_indent = self.block_indent.block_indent(self.config);
 230         }
 231         self.close_block(unindent_comment);
 232         self.last_pos = source!(self, b.span).hi();
 233     }
 234
 235     // FIXME: this is a terrible hack to indent the comments between the last
 236     // item in the block and the closing brace to the block's level.
 237     // The closing brace itself, however, should be indented at a shallower
 238     // level.
 239     fn close_block(&mut self, unindent_comment: bool) {
 240         let total_len = self.buffer.len();
 241         let chars_too_many = if unindent_comment {
 242             0
 243         } else if self.config.hard_tabs() {
 244             1
 245         } else {
 246             self.config.tab_spaces()
 247         };
 248         self.buffer.truncate(total_len - chars_too_many);
 249         self.push_str("}");
 250         self.block_indent = self.block_indent.block_unindent(self.config);
 251     }
 252
 253     // Note that this only gets called for function definitions. Required methods
 254     // on traits do not get handled here.
 255     // FIXME(topecongiro) Format async fn (#2812).
 256     fn visit_fn(
 257         &mut self,
 258         fk: visit::FnKind,
 259         generics: &ast::Generics,
 260         fd: &ast::FnDecl,
 261         s: Span,
 262         defaultness: ast::Defaultness,
 263         inner_attrs: Option<&[ast::Attribute]>,
 264     ) {
 265         let indent = self.block_indent;
 266         let block;
 267         let rewrite = match fk {
 268             visit::FnKind::ItemFn(ident, _, _, b) | visit::FnKind::Method(ident, _, _, b) => {
 269                 block = b;
 270                 self.rewrite_fn(
 271                     indent,
 272                     ident,
 273                     &FnSig::from_fn_kind(&fk, generics, fd, defaultness),
 274                     mk_sp(s.lo(), b.span.lo()),
 275                     b,
 276                     inner_attrs,
 277                 )
 278             }
 279             visit::FnKind::Closure(_) => unreachable!(),
 280         };
 281
 282         if let Some(fn_str) = rewrite {
 283             self.format_missing_with_indent(source!(self, s).lo());
 284             self.push_str(&fn_str);
 285             if let Some(c) = fn_str.chars().last() {
 286                 if c == '}' {
 287                     self.last_pos = source!(self, block.span).hi();
 288                     return;
 289                 }
 290             }
 291         } else {
 292             self.format_missing(source!(self, block.span).lo());
 293         }
 294
 295         self.last_pos = source!(self, block.span).lo();
 296         self.visit_block(block, inner_attrs, true)
 297     }
 298
 299     pub fn visit_item(&mut self, item: &ast::Item) {
 300         skip_out_of_file_lines_range_visitor!(self, item.span);
 301
 302         // This is where we bail out if there is a skip attribute. This is only
 303         // complex in the module case. It is complex because the module could be
 304         // in a separate file and there might be attributes in both files, but
 305         // the AST lumps them all together.
 306         let filtered_attrs;
 307         let mut attrs = &item.attrs;
 308         match item.node {
 309             // For use items, skip rewriting attributes. Just check for a skip attribute.
 310             ast::ItemKind::Use(..) => {
 311                 if contains_skip(attrs) {
 312                     self.push_skipped_with_span(item.span());
 313                     return;
 314                 }
 315             }
 316             // Module is inline, in this case we treat it like any other item.
 317             _ if !is_mod_decl(item) => {
 318                 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
 319                     self.push_skipped_with_span(item.span());
 320                     return;
 321                 }
 322             }
 323             // Module is not inline, but should be skipped.
 324             ast::ItemKind::Mod(..) if contains_skip(&item.attrs) => {
 325                 return;
 326             }
 327             // Module is not inline and should not be skipped. We want
 328             // to process only the attributes in the current file.
 329             ast::ItemKind::Mod(..) => {
 330                 filtered_attrs = filter_inline_attrs(&item.attrs, item.span());
 331                 // Assert because if we should skip it should be caught by
 332                 // the above case.
 333                 assert!(!self.visit_attrs(&filtered_attrs, ast::AttrStyle::Outer));
 334                 attrs = &filtered_attrs;
 335             }
 336             _ => {
 337                 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
 338                     self.push_skipped_with_span(item.span());
 339                     return;
 340                 }
 341             }
 342         }
 343
 344         match item.node {
 345             ast::ItemKind::Use(ref tree) => self.format_import(item, tree),
 346             ast::ItemKind::Impl(..) => {
 347                 let snippet = self.snippet(item.span);
 348                 let where_span_end = snippet
 349                     .find_uncommented("{")
 350                     .map(|x| BytePos(x as u32) + source!(self, item.span).lo());
 351                 let rw = format_impl(&self.get_context(), item, self.block_indent, where_span_end);
 352                 self.push_rewrite(item.span, rw);
 353             }
 354             ast::ItemKind::Trait(..) => {
 355                 let rw = format_trait(&self.get_context(), item, self.block_indent);
 356                 self.push_rewrite(item.span, rw);
 357             }
 358             ast::ItemKind::TraitAlias(ref generics, ref generic_bounds) => {
 359                 let shape = Shape::indented(self.block_indent, self.config);
 360                 let rw = format_trait_alias(
 361                     &self.get_context(),
 362                     item.ident,
 363                     generics,
 364                     generic_bounds,
 365                     shape,
 366                 );
 367                 self.push_rewrite(item.span, rw);
 368             }
 369             ast::ItemKind::ExternCrate(_) => {
 370                 let rw = rewrite_extern_crate(&self.get_context(), item);
 371                 self.push_rewrite(item.span, rw);
 372             }
 373             ast::ItemKind::Struct(..) | ast::ItemKind::Union(..) => {
 374                 self.visit_struct(&StructParts::from_item(item));
 375             }
 376             ast::ItemKind::Enum(ref def, ref generics) => {
 377                 self.format_missing_with_indent(source!(self, item.span).lo());
 378                 self.visit_enum(item.ident, &item.vis, def, generics, item.span);
 379                 self.last_pos = source!(self, item.span).hi();
 380             }
 381             ast::ItemKind::Mod(ref module) => {
 382                 let is_inline = !is_mod_decl(item);
 383                 self.format_missing_with_indent(source!(self, item.span).lo());
 384                 self.format_mod(module, &item.vis, item.span, item.ident, attrs, is_inline);
 385             }
 386             ast::ItemKind::Mac(ref mac) => {
 387                 self.visit_mac(mac, Some(item.ident), MacroPosition::Item);
 388             }
 389             ast::ItemKind::ForeignMod(ref foreign_mod) => {
 390                 self.format_missing_with_indent(source!(self, item.span).lo());
 391                 self.format_foreign_mod(foreign_mod, item.span);
 392             }
 393             ast::ItemKind::Static(..) | ast::ItemKind::Const(..) => {
 394                 self.visit_static(&StaticParts::from_item(item));
 395             }
 396             ast::ItemKind::Fn(ref decl, fn_header, ref generics, ref body) => {
 397                 let inner_attrs = inner_attributes(&item.attrs);
 398                 self.visit_fn(
 399                     visit::FnKind::ItemFn(item.ident, fn_header, &item.vis, body),
 400                     generics,
 401                     decl,
 402                     item.span,
 403                     ast::Defaultness::Final,
 404                     Some(&inner_attrs),
 405                 )
 406             }
 407             ast::ItemKind::Ty(ref ty, ref generics) => {
 408                 let rewrite = rewrite_type_alias(
 409                     &self.get_context(),
 410                     self.block_indent,
 411                     item.ident,
 412                     ty,
 413                     generics,
 414                     &item.vis,
 415                     item.span,
 416                 );
 417                 self.push_rewrite(item.span, rewrite);
 418             }
 419             ast::ItemKind::GlobalAsm(..) => {
 420                 let snippet = Some(self.snippet(item.span).to_owned());
 421                 self.push_rewrite(item.span, snippet);
 422             }
 423             ast::ItemKind::MacroDef(ref def) => {
 424                 let rewrite = rewrite_macro_def(
 425                     &self.get_context(),
 426                     self.shape(),
 427                     self.block_indent,
 428                     def,
 429                     item.ident,
 430                     &item.vis,
 431                     item.span,
 432                 );
 433                 self.push_rewrite(item.span, rewrite);
 434             }
 435         }
 436     }
 437
 438     pub fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
 439         skip_out_of_file_lines_range_visitor!(self, ti.span);
 440
 441         if self.visit_attrs(&ti.attrs, ast::AttrStyle::Outer) {
 442             self.push_skipped_with_span(ti.span());
 443             return;
 444         }
 445
 446         match ti.node {
 447             ast::TraitItemKind::Const(..) => self.visit_static(&StaticParts::from_trait_item(ti)),
 448             ast::TraitItemKind::Method(ref sig, None) => {
 449                 let indent = self.block_indent;
 450                 let rewrite =
 451                     self.rewrite_required_fn(indent, ti.ident, sig, &ti.generics, ti.span);
 452                 self.push_rewrite(ti.span, rewrite);
 453             }
 454             ast::TraitItemKind::Method(ref sig, Some(ref body)) => {
 455                 let inner_attrs = inner_attributes(&ti.attrs);
 456                 self.visit_fn(
 457                     visit::FnKind::Method(ti.ident, sig, None, body),
 458                     &ti.generics,
 459                     &sig.decl,
 460                     ti.span,
 461                     ast::Defaultness::Final,
 462                     Some(&inner_attrs),
 463                 );
 464             }
 465             ast::TraitItemKind::Type(ref generic_bounds, ref type_default) => {
 466                 let rewrite = rewrite_associated_type(
 467                     ti.ident,
 468                     type_default.as_ref(),
 469                     Some(generic_bounds),
 470                     &self.get_context(),
 471                     self.block_indent,
 472                 );
 473                 self.push_rewrite(ti.span, rewrite);
 474             }
 475             ast::TraitItemKind::Macro(ref mac) => {
 476                 self.visit_mac(mac, Some(ti.ident), MacroPosition::Item);
 477             }
 478         }
 479     }
 480
 481     pub fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
 482         skip_out_of_file_lines_range_visitor!(self, ii.span);
 483
 484         if self.visit_attrs(&ii.attrs, ast::AttrStyle::Outer) {
 485             self.push_skipped_with_span(ii.span());
 486             return;
 487         }
 488
 489         match ii.node {
 490             ast::ImplItemKind::Method(ref sig, ref body) => {
 491                 let inner_attrs = inner_attributes(&ii.attrs);
 492                 self.visit_fn(
 493                     visit::FnKind::Method(ii.ident, sig, Some(&ii.vis), body),
 494                     &ii.generics,
 495                     &sig.decl,
 496                     ii.span,
 497                     ii.defaultness,
 498                     Some(&inner_attrs),
 499                 );
 500             }
 501             ast::ImplItemKind::Const(..) => self.visit_static(&StaticParts::from_impl_item(ii)),
 502             ast::ImplItemKind::Type(ref ty) => {
 503                 let rewrite = rewrite_associated_impl_type(
 504                     ii.ident,
 505                     ii.defaultness,
 506                     Some(ty),
 507                     None,
 508                     &self.get_context(),
 509                     self.block_indent,
 510                 );
 511                 self.push_rewrite(ii.span, rewrite);
 512             }
 513             ast::ImplItemKind::Macro(ref mac) => {
 514                 self.visit_mac(mac, Some(ii.ident), MacroPosition::Item);
 515             }
 516         }
 517     }
 518
 519     fn visit_mac(&mut self, mac: &ast::Mac, ident: Option<ast::Ident>, pos: MacroPosition) {
 520         skip_out_of_file_lines_range_visitor!(self, mac.span);
 521
 522         // 1 = ;
 523         let shape = self.shape().sub_width(1).unwrap();
 524         let rewrite = self.with_context(|ctx| rewrite_macro(mac, ident, ctx, shape, pos));
 525         self.push_rewrite(mac.span, rewrite);
 526     }
 527
 528     pub fn push_str(&mut self, s: &str) {
 529         self.line_number += count_newlines(s);
 530         self.buffer.push_str(s);
 531     }
 532
 533     #[cfg_attr(feature = "cargo-clippy", allow(needless_pass_by_value))]
 534     fn push_rewrite_inner(&mut self, span: Span, rewrite: Option<String>) {
 535         if let Some(ref s) = rewrite {
 536             self.push_str(s);
 537         } else {
 538             let snippet = self.snippet(span);
 539             self.push_str(snippet);
 540         }
 541         self.last_pos = source!(self, span).hi();
 542     }
 543
 544     pub fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
 545         self.format_missing_with_indent(source!(self, span).lo());
 546         self.push_rewrite_inner(span, rewrite);
 547     }
 548
 549     pub fn push_skipped_with_span(&mut self, span: Span) {
 550         self.format_missing_with_indent(source!(self, span).lo());
 551         let lo = self.line_number + 1;
 552         self.push_rewrite_inner(span, None);
 553         let hi = self.line_number + 1;
 554         self.skipped_range.push((lo, hi));
 555     }
 556
 557     pub fn from_context(ctx: &'a RewriteContext) -> FmtVisitor<'a> {
 558         FmtVisitor::from_codemap(
 559             ctx.parse_session,
 560             ctx.config,
 561             ctx.snippet_provider,
 562             ctx.report.clone(),
 563         )
 564     }
 565
 566     pub(crate) fn from_codemap(
 567         parse_session: &'a ParseSess,
 568         config: &'a Config,
 569         snippet_provider: &'a SnippetProvider,
 570         report: FormatReport,
 571     ) -> FmtVisitor<'a> {
 572         FmtVisitor {
 573             parse_session,
 574             codemap: parse_session.codemap(),
 575             buffer: String::with_capacity(snippet_provider.big_snippet.len() * 2),
 576             last_pos: BytePos(0),
 577             block_indent: Indent::empty(),
 578             config,
 579             is_if_else_block: false,
 580             snippet_provider,
 581             line_number: 0,
 582             skipped_range: vec![],
 583             macro_rewrite_failure: false,
 584             report,
 585         }
 586     }
 587
 588     pub fn opt_snippet(&'b self, span: Span) -> Option<&'a str> {
 589         self.snippet_provider.span_to_snippet(span)
 590     }
 591
 592     pub fn snippet(&'b self, span: Span) -> &'a str {
 593         self.opt_snippet(span).unwrap()
 594     }
 595
 596     // Returns true if we should skip the following item.
 597     pub fn visit_attrs(&mut self, attrs: &[ast::Attribute], style: ast::AttrStyle) -> bool {
 598         for attr in attrs {
 599             if attr.name() == DEPR_SKIP_ANNOTATION {
 600                 let file_name = self.codemap.span_to_filename(attr.span).into();
 601                 self.report.append(
 602                     file_name,
 603                     vec![FormattingError::from_span(
 604                         &attr.span,
 605                         &self.codemap,
 606                         ErrorKind::DeprecatedAttr,
 607                     )],
 608                 );
 609             } else if attr.path.segments[0].ident.to_string() == "rustfmt" {
 610                 if attr.path.segments.len() == 1
 611                     || attr.path.segments[1].ident.to_string() != "skip"
 612                 {
 613                     let file_name = self.codemap.span_to_filename(attr.span).into();
 614                     self.report.append(
 615                         file_name,
 616                         vec![FormattingError::from_span(
 617                             &attr.span,
 618                             &self.codemap,
 619                             ErrorKind::BadAttr,
 620                         )],
 621                     );
 622                 }
 623             }
 624         }
 625         if contains_skip(attrs) {
 626             return true;
 627         }
 628
 629         let attrs: Vec<_> = attrs.iter().filter(|a| a.style == style).cloned().collect();
 630         if attrs.is_empty() {
 631             return false;
 632         }
 633
 634         let rewrite = attrs.rewrite(&self.get_context(), self.shape());
 635         let span = mk_sp(attrs[0].span.lo(), attrs[attrs.len() - 1].span.hi());
 636         self.push_rewrite(span, rewrite);
 637
 638         false
 639     }
 640
 641     fn walk_mod_items(&mut self, m: &ast::Mod) {
 642         self.visit_items_with_reordering(&ptr_vec_to_ref_vec(&m.items));
 643     }
 644
 645     fn walk_stmts(&mut self, stmts: &[ast::Stmt]) {
 646         fn to_stmt_item(stmt: &ast::Stmt) -> Option<&ast::Item> {
 647             match stmt.node {
 648                 ast::StmtKind::Item(ref item) => Some(&**item),
 649                 _ => None,
 650             }
 651         }
 652
 653         if stmts.is_empty() {
 654             return;
 655         }
 656
 657         // Extract leading `use ...;`.
 658         let items: Vec<_> = stmts
 659             .iter()
 660             .take_while(|stmt| to_stmt_item(stmt).map_or(false, is_use_item))
 661             .filter_map(|stmt| to_stmt_item(stmt))
 662             .collect();
 663
 664         if items.is_empty() {
 665             self.visit_stmt(&stmts[0]);
 666             self.walk_stmts(&stmts[1..]);
 667         } else {
 668             self.visit_items_with_reordering(&items);
 669             self.walk_stmts(&stmts[items.len()..]);
 670         }
 671     }
 672
 673     fn walk_block_stmts(&mut self, b: &ast::Block) {
 674         self.walk_stmts(&b.stmts)
 675     }
 676
 677     fn format_mod(
 678         &mut self,
 679         m: &ast::Mod,
 680         vis: &ast::Visibility,
 681         s: Span,
 682         ident: ast::Ident,
 683         attrs: &[ast::Attribute],
 684         is_internal: bool,
 685     ) {
 686         let vis_str = utils::format_visibility(&self.get_context(), vis);
 687         self.push_str(&*vis_str);
 688         self.push_str("mod ");
 689         // Calling `to_owned()` to work around borrow checker.
 690         let ident_str = rewrite_ident(&self.get_context(), ident).to_owned();
 691         self.push_str(&ident_str);
 692
 693         if is_internal {
 694             match self.config.brace_style() {
 695                 BraceStyle::AlwaysNextLine => {
 696                     let indent_str = self.block_indent.to_string_with_newline(self.config);
 697                     self.push_str(&indent_str);
 698                     self.push_str("{");
 699                 }
 700                 _ => self.push_str(" {"),
 701             }
 702             // Hackery to account for the closing }.
 703             let mod_lo = self.snippet_provider.span_after(source!(self, s), "{");
 704             let body_snippet =
 705                 self.snippet(mk_sp(mod_lo, source!(self, m.inner).hi() - BytePos(1)));
 706             let body_snippet = body_snippet.trim();
 707             if body_snippet.is_empty() {
 708                 self.push_str("}");
 709             } else {
 710                 self.last_pos = mod_lo;
 711                 self.block_indent = self.block_indent.block_indent(self.config);
 712                 self.visit_attrs(attrs, ast::AttrStyle::Inner);
 713                 self.walk_mod_items(m);
 714                 self.format_missing_with_indent(source!(self, m.inner).hi() - BytePos(1));
 715                 self.close_block(false);
 716             }
 717             self.last_pos = source!(self, m.inner).hi();
 718         } else {
 719             self.push_str(";");
 720             self.last_pos = source!(self, s).hi();
 721         }
 722     }
 723
 724     pub fn format_separate_mod(&mut self, m: &ast::Mod, filemap: &codemap::FileMap) {
 725         self.block_indent = Indent::empty();
 726         self.walk_mod_items(m);
 727         self.format_missing_with_indent(filemap.end_pos);
 728     }
 729
 730     pub fn skip_empty_lines(&mut self, end_pos: BytePos) {
 731         while let Some(pos) = self
 732             .snippet_provider
 733             .opt_span_after(mk_sp(self.last_pos, end_pos), "\n")
 734         {
 735             if let Some(snippet) = self.opt_snippet(mk_sp(self.last_pos, pos)) {
 736                 if snippet.trim().is_empty() {
 737                     self.last_pos = pos;
 738                 } else {
 739                     return;
 740                 }
 741             }
 742         }
 743     }
 744
 745     pub fn with_context<F>(&mut self, f: F) -> Option<String>
 746     where
 747         F: Fn(&RewriteContext) -> Option<String>,
 748     {
 749         let result;
 750         let macro_rewrite_failure = {
 751             let context = self.get_context();
 752             result = f(&context);
 753             unsafe { *context.macro_rewrite_failure.as_ptr() }
 754         };
 755         self.macro_rewrite_failure |= macro_rewrite_failure;
 756         result
 757     }
 758
 759     pub fn get_context(&self) -> RewriteContext {
 760         RewriteContext {
 761             parse_session: self.parse_session,
 762             codemap: self.codemap,
 763             config: self.config,
 764             inside_macro: RefCell::new(false),
 765             use_block: RefCell::new(false),
 766             is_if_else_block: RefCell::new(false),
 767             force_one_line_chain: RefCell::new(false),
 768             snippet_provider: self.snippet_provider,
 769             macro_rewrite_failure: RefCell::new(false),
 770             report: self.report.clone(),
 771         }
 772     }
 773 }