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