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 std::cmp;
  12
  13 use strings::string_buffer::StringBuffer;
  14 use syntax::{ast, ptr, visit};
  15 use syntax::codemap::{BytePos, CodeMap, Span};
  16 use syntax::parse::ParseSess;
  17
  18 use {Indent, Shape};
  19 use codemap::{LineRangeUtils, SpanUtils};
  20 use comment::{contains_comment, FindUncommented};
  21 use comment::rewrite_comment;
  22 use config::{BraceStyle, Config};
  23 use expr::{format_expr, ExprType};
  24 use items::{format_impl, format_trait, rewrite_associated_impl_type, rewrite_associated_type,
  25             rewrite_static, rewrite_type_alias};
  26 use lists::{itemize_list, write_list, DefinitiveListTactic, ListFormatting, SeparatorTactic};
  27 use macros::{rewrite_macro, MacroPosition};
  28 use rewrite::{Rewrite, RewriteContext};
  29 use utils::{self, contains_skip, mk_sp};
  30
  31 fn is_use_item(item: &ast::Item) -> bool {
  32     match item.node {
  33         ast::ItemKind::Use(_) => true,
  34         _ => false,
  35     }
  36 }
  37
  38 fn item_bound(item: &ast::Item) -> Span {
  39     item.attrs.iter().map(|attr| attr.span).fold(
  40         item.span,
  41         |bound, span| {
  42             Span {
  43                 lo: cmp::min(bound.lo, span.lo),
  44                 hi: cmp::max(bound.hi, span.hi),
  45                 ctxt: span.ctxt,
  46             }
  47         },
  48     )
  49 }
  50
  51 pub struct FmtVisitor<'a> {
  52     pub parse_session: &'a ParseSess,
  53     pub codemap: &'a CodeMap,
  54     pub buffer: StringBuffer,
  55     pub last_pos: BytePos,
  56     // FIXME: use an RAII util or closure for indenting
  57     pub block_indent: Indent,
  58     pub config: &'a Config,
  59     pub is_if_else_block: bool,
  60 }
  61
  62 impl<'a> FmtVisitor<'a> {
  63     fn visit_stmt(&mut self, stmt: &ast::Stmt) {
  64         debug!(
  65             "visit_stmt: {:?} {:?}",
  66             self.codemap.lookup_char_pos(stmt.span.lo),
  67             self.codemap.lookup_char_pos(stmt.span.hi)
  68         );
  69
  70         // FIXME(#434): Move this check to somewhere more central, eg Rewrite.
  71         if !self.config
  72             .file_lines()
  73             .intersects(&self.codemap.lookup_line_range(stmt.span))
  74         {
  75             return;
  76         }
  77
  78         match stmt.node {
  79             ast::StmtKind::Item(ref item) => {
  80                 self.visit_item(item);
  81             }
  82             ast::StmtKind::Local(ref local) => {
  83                 let rewrite = if contains_skip(&local.attrs) {
  84                     None
  85                 } else {
  86                     stmt.rewrite(
  87                         &self.get_context(),
  88                         Shape::indented(self.block_indent, self.config),
  89                     )
  90                 };
  91                 self.push_rewrite(stmt.span, rewrite);
  92             }
  93             ast::StmtKind::Expr(ref expr) => {
  94                 let rewrite = format_expr(
  95                     expr,
  96                     ExprType::Statement,
  97                     &self.get_context(),
  98                     Shape::indented(self.block_indent, self.config),
  99                 );
 100                 let span = if expr.attrs.is_empty() {
 101                     stmt.span
 102                 } else {
 103                     mk_sp(expr.attrs[0].span.lo, stmt.span.hi)
 104                 };
 105                 self.push_rewrite(span, rewrite)
 106             }
 107             ast::StmtKind::Semi(ref expr) => {
 108                 let rewrite = stmt.rewrite(
 109                     &self.get_context(),
 110                     Shape::indented(self.block_indent, self.config),
 111                 );
 112                 let span = if expr.attrs.is_empty() {
 113                     stmt.span
 114                 } else {
 115                     mk_sp(expr.attrs[0].span.lo, stmt.span.hi)
 116                 };
 117                 self.push_rewrite(span, rewrite)
 118             }
 119             ast::StmtKind::Mac(ref mac) => {
 120                 let (ref mac, _macro_style, ref attrs) = **mac;
 121                 if contains_skip(attrs) {
 122                     self.push_rewrite(mac.span, None);
 123                 } else {
 124                     self.visit_mac(mac, None, MacroPosition::Statement);
 125                 }
 126                 self.format_missing(stmt.span.hi);
 127             }
 128         }
 129     }
 130
 131     pub fn visit_block(&mut self, b: &ast::Block) {
 132         debug!(
 133             "visit_block: {:?} {:?}",
 134             self.codemap.lookup_char_pos(b.span.lo),
 135             self.codemap.lookup_char_pos(b.span.hi)
 136         );
 137
 138         // Check if this block has braces.
 139         let snippet = self.snippet(b.span);
 140         let has_braces = snippet.starts_with('{') || snippet.starts_with("unsafe");
 141         let brace_compensation = if has_braces { BytePos(1) } else { BytePos(0) };
 142
 143         self.last_pos = self.last_pos + brace_compensation;
 144         self.block_indent = self.block_indent.block_indent(self.config);
 145         self.buffer.push_str("{");
 146
 147         for stmt in &b.stmts {
 148             self.visit_stmt(stmt)
 149         }
 150
 151         if !b.stmts.is_empty() {
 152             if let Some(expr) = utils::stmt_expr(&b.stmts[b.stmts.len() - 1]) {
 153                 if utils::semicolon_for_expr(&self.get_context(), expr) {
 154                     self.buffer.push_str(";");
 155                 }
 156             }
 157         }
 158
 159         let mut unindent_comment = self.is_if_else_block && !b.stmts.is_empty();
 160         if unindent_comment {
 161             let end_pos = source!(self, b.span).hi - brace_compensation;
 162             let snippet = self.get_context().snippet(mk_sp(self.last_pos, end_pos));
 163             unindent_comment = snippet.contains("//") || snippet.contains("/*");
 164         }
 165         // FIXME: we should compress any newlines here to just one
 166         if unindent_comment {
 167             self.block_indent = self.block_indent.block_unindent(self.config);
 168         }
 169         self.format_missing_with_indent(source!(self, b.span).hi - brace_compensation);
 170         if unindent_comment {
 171             self.block_indent = self.block_indent.block_indent(self.config);
 172         }
 173         self.close_block(unindent_comment);
 174         self.last_pos = source!(self, b.span).hi;
 175     }
 176
 177     // FIXME: this is a terrible hack to indent the comments between the last
 178     // item in the block and the closing brace to the block's level.
 179     // The closing brace itself, however, should be indented at a shallower
 180     // level.
 181     fn close_block(&mut self, unindent_comment: bool) {
 182         let total_len = self.buffer.len;
 183         let chars_too_many = if unindent_comment {
 184             0
 185         } else if self.config.hard_tabs() {
 186             1
 187         } else {
 188             self.config.tab_spaces()
 189         };
 190         self.buffer.truncate(total_len - chars_too_many);
 191         self.buffer.push_str("}");
 192         self.block_indent = self.block_indent.block_unindent(self.config);
 193     }
 194
 195     // Note that this only gets called for function definitions. Required methods
 196     // on traits do not get handled here.
 197     fn visit_fn(
 198         &mut self,
 199         fk: visit::FnKind,
 200         fd: &ast::FnDecl,
 201         s: Span,
 202         _: ast::NodeId,
 203         defaultness: ast::Defaultness,
 204     ) {
 205         let indent = self.block_indent;
 206         let block;
 207         let rewrite = match fk {
 208             visit::FnKind::ItemFn(ident, generics, unsafety, constness, abi, vis, b) => {
 209                 block = b;
 210                 self.rewrite_fn(
 211                     indent,
 212                     ident,
 213                     fd,
 214                     generics,
 215                     unsafety,
 216                     constness.node,
 217                     defaultness,
 218                     abi,
 219                     vis,
 220                     mk_sp(s.lo, b.span.lo),
 221                     &b,
 222                 )
 223             }
 224             visit::FnKind::Method(ident, sig, vis, b) => {
 225                 block = b;
 226                 self.rewrite_fn(
 227                     indent,
 228                     ident,
 229                     fd,
 230                     &sig.generics,
 231                     sig.unsafety,
 232                     sig.constness.node,
 233                     defaultness,
 234                     sig.abi,
 235                     vis.unwrap_or(&ast::Visibility::Inherited),
 236                     mk_sp(s.lo, b.span.lo),
 237                     &b,
 238                 )
 239             }
 240             visit::FnKind::Closure(_) => unreachable!(),
 241         };
 242
 243         if let Some(fn_str) = rewrite {
 244             self.format_missing_with_indent(source!(self, s).lo);
 245             self.buffer.push_str(&fn_str);
 246             if let Some(c) = fn_str.chars().last() {
 247                 if c == '}' {
 248                     self.last_pos = source!(self, block.span).hi;
 249                     return;
 250                 }
 251             }
 252         } else {
 253             self.format_missing(source!(self, block.span).lo);
 254         }
 255
 256         self.last_pos = source!(self, block.span).lo;
 257         self.visit_block(block)
 258     }
 259
 260     pub fn visit_item(&mut self, item: &ast::Item) {
 261         // This is where we bail out if there is a skip attribute. This is only
 262         // complex in the module case. It is complex because the module could be
 263         // in a separate file and there might be attributes in both files, but
 264         // the AST lumps them all together.
 265         match item.node {
 266             ast::ItemKind::Mod(ref m) => {
 267                 let outer_file = self.codemap.lookup_char_pos(item.span.lo).file;
 268                 let inner_file = self.codemap.lookup_char_pos(m.inner.lo).file;
 269                 if outer_file.name == inner_file.name {
 270                     // Module is inline, in this case we treat modules like any
 271                     // other item.
 272                     if self.visit_attrs(&item.attrs) {
 273                         self.push_rewrite(item.span, None);
 274                         return;
 275                     }
 276                 } else if utils::contains_skip(&item.attrs) {
 277                     // Module is not inline, but should be skipped.
 278                     return;
 279                 } else {
 280                     // Module is not inline and should not be skipped. We want
 281                     // to process only the attributes in the current file.
 282                     let attrs = item.attrs
 283                         .iter()
 284                         .filter_map(|a| {
 285                             let attr_file = self.codemap.lookup_char_pos(a.span.lo).file;
 286                             if attr_file.name == outer_file.name {
 287                                 Some(a.clone())
 288                             } else {
 289                                 None
 290                             }
 291                         })
 292                         .collect::<Vec<_>>();
 293                     // Assert because if we should skip it should be caught by
 294                     // the above case.
 295                     assert!(!self.visit_attrs(&attrs));
 296                 }
 297             }
 298             _ => if self.visit_attrs(&item.attrs) {
 299                 self.push_rewrite(item.span, None);
 300                 return;
 301             },
 302         }
 303
 304         match item.node {
 305             ast::ItemKind::Use(ref vp) => {
 306                 self.format_import(&item.vis, vp, item.span);
 307             }
 308             ast::ItemKind::Impl(..) => {
 309                 self.format_missing_with_indent(source!(self, item.span).lo);
 310                 let snippet = self.get_context().snippet(item.span);
 311                 let where_span_end = snippet
 312                     .find_uncommented("{")
 313                     .map(|x| (BytePos(x as u32)) + source!(self, item.span).lo);
 314                 if let Some(impl_str) =
 315                     format_impl(&self.get_context(), item, self.block_indent, where_span_end)
 316                 {
 317                     self.buffer.push_str(&impl_str);
 318                     self.last_pos = source!(self, item.span).hi;
 319                 }
 320             }
 321             ast::ItemKind::Trait(..) => {
 322                 self.format_missing_with_indent(item.span.lo);
 323                 if let Some(trait_str) =
 324                     format_trait(&self.get_context(), item, self.block_indent)
 325                 {
 326                     self.buffer.push_str(&trait_str);
 327                     self.last_pos = source!(self, item.span).hi;
 328                 }
 329             }
 330             ast::ItemKind::ExternCrate(_) => {
 331                 self.format_missing_with_indent(source!(self, item.span).lo);
 332                 let new_str = self.snippet(item.span);
 333                 self.buffer.push_str(&new_str);
 334                 self.last_pos = source!(self, item.span).hi;
 335             }
 336             ast::ItemKind::Struct(ref def, ref generics) => {
 337                 let rewrite = {
 338                     let indent = self.block_indent;
 339                     let context = self.get_context();
 340                     ::items::format_struct(
 341                         &context,
 342                         "struct ",
 343                         item.ident,
 344                         &item.vis,
 345                         def,
 346                         Some(generics),
 347                         item.span,
 348                         indent,
 349                         None,
 350                     ).map(|s| match *def {
 351                         ast::VariantData::Tuple(..) => s + ";",
 352                         _ => s,
 353                     })
 354                 };
 355                 self.push_rewrite(item.span, rewrite);
 356             }
 357             ast::ItemKind::Enum(ref def, ref generics) => {
 358                 self.format_missing_with_indent(source!(self, item.span).lo);
 359                 self.visit_enum(item.ident, &item.vis, def, generics, item.span);
 360                 self.last_pos = source!(self, item.span).hi;
 361             }
 362             ast::ItemKind::Mod(ref module) => {
 363                 self.format_missing_with_indent(source!(self, item.span).lo);
 364                 self.format_mod(module, &item.vis, item.span, item.ident);
 365             }
 366             ast::ItemKind::Mac(ref mac) => {
 367                 self.visit_mac(mac, Some(item.ident), MacroPosition::Item);
 368             }
 369             ast::ItemKind::ForeignMod(ref foreign_mod) => {
 370                 self.format_missing_with_indent(source!(self, item.span).lo);
 371                 self.format_foreign_mod(foreign_mod, item.span);
 372             }
 373             ast::ItemKind::Static(ref ty, mutability, ref expr) => {
 374                 let rewrite = rewrite_static(
 375                     "static",
 376                     &item.vis,
 377                     item.ident,
 378                     ty,
 379                     mutability,
 380                     Some(expr),
 381                     self.block_indent,
 382                     item.span,
 383                     &self.get_context(),
 384                 );
 385                 self.push_rewrite(item.span, rewrite);
 386             }
 387             ast::ItemKind::Const(ref ty, ref expr) => {
 388                 let rewrite = rewrite_static(
 389                     "const",
 390                     &item.vis,
 391                     item.ident,
 392                     ty,
 393                     ast::Mutability::Immutable,
 394                     Some(expr),
 395                     self.block_indent,
 396                     item.span,
 397                     &self.get_context(),
 398                 );
 399                 self.push_rewrite(item.span, rewrite);
 400             }
 401             ast::ItemKind::DefaultImpl(..) => {
 402                 // FIXME(#78): format impl definitions.
 403             }
 404             ast::ItemKind::Fn(ref decl, unsafety, constness, abi, ref generics, ref body) => {
 405                 self.visit_fn(
 406                     visit::FnKind::ItemFn(
 407                         item.ident,
 408                         generics,
 409                         unsafety,
 410                         constness,
 411                         abi,
 412                         &item.vis,
 413                         body,
 414                     ),
 415                     decl,
 416                     item.span,
 417                     item.id,
 418                     ast::Defaultness::Final,
 419                 )
 420             }
 421             ast::ItemKind::Ty(ref ty, ref generics) => {
 422                 let rewrite = rewrite_type_alias(
 423                     &self.get_context(),
 424                     self.block_indent,
 425                     item.ident,
 426                     ty,
 427                     generics,
 428                     &item.vis,
 429                     item.span,
 430                 );
 431                 self.push_rewrite(item.span, rewrite);
 432             }
 433             ast::ItemKind::Union(ref def, ref generics) => {
 434                 let rewrite = ::items::format_struct_struct(
 435                     &self.get_context(),
 436                     "union ",
 437                     item.ident,
 438                     &item.vis,
 439                     def.fields(),
 440                     Some(generics),
 441                     item.span,
 442                     self.block_indent,
 443                     None,
 444                 );
 445                 self.push_rewrite(item.span, rewrite);
 446             }
 447             ast::ItemKind::GlobalAsm(..) => {
 448                 let snippet = Some(self.snippet(item.span));
 449                 self.push_rewrite(item.span, snippet);
 450             }
 451             ast::ItemKind::MacroDef(..) => {
 452                 // FIXME(#1539): macros 2.0
 453                 let snippet = Some(self.snippet(item.span));
 454                 self.push_rewrite(item.span, snippet);
 455             }
 456         }
 457     }
 458
 459     pub fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
 460         if self.visit_attrs(&ti.attrs) {
 461             self.push_rewrite(ti.span, None);
 462             return;
 463         }
 464
 465         match ti.node {
 466             ast::TraitItemKind::Const(ref ty, ref expr_opt) => {
 467                 let rewrite = rewrite_static(
 468                     "const",
 469                     &ast::Visibility::Inherited,
 470                     ti.ident,
 471                     ty,
 472                     ast::Mutability::Immutable,
 473                     expr_opt.as_ref(),
 474                     self.block_indent,
 475                     ti.span,
 476                     &self.get_context(),
 477                 );
 478                 self.push_rewrite(ti.span, rewrite);
 479             }
 480             ast::TraitItemKind::Method(ref sig, None) => {
 481                 let indent = self.block_indent;
 482                 let rewrite = self.rewrite_required_fn(indent, ti.ident, sig, ti.span);
 483                 self.push_rewrite(ti.span, rewrite);
 484             }
 485             ast::TraitItemKind::Method(ref sig, Some(ref body)) => {
 486                 self.visit_fn(
 487                     visit::FnKind::Method(ti.ident, sig, None, body),
 488                     &sig.decl,
 489                     ti.span,
 490                     ti.id,
 491                     ast::Defaultness::Final,
 492                 );
 493             }
 494             ast::TraitItemKind::Type(ref type_param_bounds, ref type_default) => {
 495                 let rewrite = rewrite_associated_type(
 496                     ti.ident,
 497                     type_default.as_ref(),
 498                     Some(type_param_bounds),
 499                     &self.get_context(),
 500                     self.block_indent,
 501                 );
 502                 self.push_rewrite(ti.span, rewrite);
 503             }
 504             ast::TraitItemKind::Macro(ref mac) => {
 505                 self.visit_mac(mac, Some(ti.ident), MacroPosition::Item);
 506             }
 507         }
 508     }
 509
 510     pub fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
 511         if self.visit_attrs(&ii.attrs) {
 512             self.push_rewrite(ii.span, None);
 513             return;
 514         }
 515
 516         match ii.node {
 517             ast::ImplItemKind::Method(ref sig, ref body) => {
 518                 self.visit_fn(
 519                     visit::FnKind::Method(ii.ident, sig, Some(&ii.vis), body),
 520                     &sig.decl,
 521                     ii.span,
 522                     ii.id,
 523                     ii.defaultness,
 524                 );
 525             }
 526             ast::ImplItemKind::Const(ref ty, ref expr) => {
 527                 let rewrite = rewrite_static(
 528                     "const",
 529                     &ii.vis,
 530                     ii.ident,
 531                     ty,
 532                     ast::Mutability::Immutable,
 533                     Some(expr),
 534                     self.block_indent,
 535                     ii.span,
 536                     &self.get_context(),
 537                 );
 538                 self.push_rewrite(ii.span, rewrite);
 539             }
 540             ast::ImplItemKind::Type(ref ty) => {
 541                 let rewrite = rewrite_associated_impl_type(
 542                     ii.ident,
 543                     ii.defaultness,
 544                     Some(ty),
 545                     None,
 546                     &self.get_context(),
 547                     self.block_indent,
 548                 );
 549                 self.push_rewrite(ii.span, rewrite);
 550             }
 551             ast::ImplItemKind::Macro(ref mac) => {
 552                 self.visit_mac(mac, Some(ii.ident), MacroPosition::Item);
 553             }
 554         }
 555     }
 556
 557     fn visit_mac(&mut self, mac: &ast::Mac, ident: Option<ast::Ident>, pos: MacroPosition) {
 558         // 1 = ;
 559         let shape = Shape::indented(self.block_indent, self.config)
 560             .sub_width(1)
 561             .unwrap();
 562         let rewrite = rewrite_macro(mac, ident, &self.get_context(), shape, pos);
 563         self.push_rewrite(mac.span, rewrite);
 564     }
 565
 566     fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
 567         self.format_missing_with_indent(source!(self, span).lo);
 568         let result = rewrite.unwrap_or_else(|| self.snippet(span));
 569         self.buffer.push_str(&result);
 570         self.last_pos = source!(self, span).hi;
 571     }
 572
 573     pub fn from_codemap(parse_session: &'a ParseSess, config: &'a Config) -> FmtVisitor<'a> {
 574         FmtVisitor {
 575             parse_session: parse_session,
 576             codemap: parse_session.codemap(),
 577             buffer: StringBuffer::new(),
 578             last_pos: BytePos(0),
 579             block_indent: Indent::empty(),
 580             config: config,
 581             is_if_else_block: false,
 582         }
 583     }
 584
 585     pub fn snippet(&self, span: Span) -> String {
 586         match self.codemap.span_to_snippet(span) {
 587             Ok(s) => s,
 588             Err(_) => {
 589                 println!(
 590                     "Couldn't make snippet for span {:?}->{:?}",
 591                     self.codemap.lookup_char_pos(span.lo),
 592                     self.codemap.lookup_char_pos(span.hi)
 593                 );
 594                 "".to_owned()
 595             }
 596         }
 597     }
 598
 599     // Returns true if we should skip the following item.
 600     pub fn visit_attrs(&mut self, attrs: &[ast::Attribute]) -> bool {
 601         if utils::contains_skip(attrs) {
 602             return true;
 603         }
 604
 605         let outers: Vec<_> = attrs
 606             .iter()
 607             .filter(|a| a.style == ast::AttrStyle::Outer)
 608             .cloned()
 609             .collect();
 610         if outers.is_empty() {
 611             return false;
 612         }
 613
 614         let first = &outers[0];
 615         self.format_missing_with_indent(source!(self, first.span).lo);
 616
 617         let rewrite = outers
 618             .rewrite(
 619                 &self.get_context(),
 620                 Shape::indented(self.block_indent, self.config),
 621             )
 622             .unwrap();
 623         self.buffer.push_str(&rewrite);
 624         let last = outers.last().unwrap();
 625         self.last_pos = source!(self, last.span).hi;
 626         false
 627     }
 628
 629     fn walk_mod_items(&mut self, m: &ast::Mod) {
 630         let mut items_left: &[ptr::P<ast::Item>] = &m.items;
 631         while !items_left.is_empty() {
 632             // If the next item is a `use` declaration, then extract it and any subsequent `use`s
 633             // to be potentially reordered within `format_imports`. Otherwise, just format the
 634             // next item for output.
 635             if self.config.reorder_imports() && is_use_item(&*items_left[0]) {
 636                 let reorder_imports_in_group = self.config.reorder_imports_in_group();
 637                 let mut last = self.codemap.lookup_line_range(item_bound(&items_left[0]));
 638                 let use_item_length = items_left
 639                     .iter()
 640                     .take_while(|ppi| {
 641                         is_use_item(&***ppi) &&
 642                             (!reorder_imports_in_group ||
 643                                 {
 644                                     let current = self.codemap.lookup_line_range(item_bound(&ppi));
 645                                     let in_same_group = current.lo < last.hi + 2;
 646                                     last = current;
 647                                     in_same_group
 648                                 })
 649                     })
 650                     .count();
 651                 let (use_items, rest) = items_left.split_at(use_item_length);
 652                 self.format_imports(use_items);
 653                 items_left = rest;
 654             } else {
 655                 // `unwrap()` is safe here because we know `items_left`
 656                 // has elements from the loop condition
 657                 let (item, rest) = items_left.split_first().unwrap();
 658                 self.visit_item(item);
 659                 items_left = rest;
 660             }
 661         }
 662     }
 663
 664     fn format_mod(&mut self, m: &ast::Mod, vis: &ast::Visibility, s: Span, ident: ast::Ident) {
 665         // Decide whether this is an inline mod or an external mod.
 666         let local_file_name = self.codemap.span_to_filename(s);
 667         let inner_span = source!(self, m.inner);
 668         let is_internal = !(inner_span.lo.0 == 0 && inner_span.hi.0 == 0) &&
 669             local_file_name == self.codemap.span_to_filename(inner_span);
 670
 671         self.buffer.push_str(&*utils::format_visibility(vis));
 672         self.buffer.push_str("mod ");
 673         self.buffer.push_str(&ident.to_string());
 674
 675         if is_internal {
 676             match self.config.item_brace_style() {
 677                 BraceStyle::AlwaysNextLine => self.buffer
 678                     .push_str(&format!("\n{}{{", self.block_indent.to_string(self.config))),
 679                 _ => self.buffer.push_str(" {"),
 680             }
 681             // Hackery to account for the closing }.
 682             let mod_lo = self.codemap.span_after(source!(self, s), "{");
 683             let body_snippet = self.snippet(mk_sp(mod_lo, source!(self, m.inner).hi - BytePos(1)));
 684             let body_snippet = body_snippet.trim();
 685             if body_snippet.is_empty() {
 686                 self.buffer.push_str("}");
 687             } else {
 688                 self.last_pos = mod_lo;
 689                 self.block_indent = self.block_indent.block_indent(self.config);
 690                 self.walk_mod_items(m);
 691                 self.format_missing_with_indent(source!(self, m.inner).hi - BytePos(1));
 692                 self.close_block(false);
 693             }
 694             self.last_pos = source!(self, m.inner).hi;
 695         } else {
 696             self.buffer.push_str(";");
 697             self.last_pos = source!(self, s).hi;
 698         }
 699     }
 700
 701     pub fn format_separate_mod(&mut self, m: &ast::Mod) {
 702         let filemap = self.codemap.lookup_char_pos(m.inner.lo).file;
 703         self.last_pos = filemap.start_pos;
 704         self.block_indent = Indent::empty();
 705         self.walk_mod_items(m);
 706         self.format_missing_with_indent(filemap.end_pos);
 707     }
 708
 709     pub fn get_context(&self) -> RewriteContext {
 710         RewriteContext {
 711             parse_session: self.parse_session,
 712             codemap: self.codemap,
 713             config: self.config,
 714             inside_macro: false,
 715             use_block: false,
 716             is_if_else_block: false,
 717             force_one_line_chain: false,
 718         }
 719     }
 720 }
 721
 722 impl Rewrite for ast::NestedMetaItem {
 723     fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
 724         match self.node {
 725             ast::NestedMetaItemKind::MetaItem(ref meta_item) => meta_item.rewrite(context, shape),
 726             ast::NestedMetaItemKind::Literal(..) => Some(context.snippet(self.span)),
 727         }
 728     }
 729 }
 730
 731 fn count_missing_closing_parens(s: &str) -> u32 {
 732     let mut op_parens: u32 = 0;
 733     let mut cl_parens: u32 = 0;
 734
 735     #[derive(Eq, PartialEq)]
 736     pub enum SnippetState {
 737         Normal,
 738         InsideStr,
 739         InsideBulletComment,
 740         InsideSingleLineComment,
 741     }
 742
 743     let mut state = SnippetState::Normal;
 744     let mut iter = s.chars().peekable();
 745     let mut prev_char: Option<char> = None;
 746     while let Some(c) = iter.next() {
 747         let next_char = iter.peek();
 748         match c {
 749             '/' if state == SnippetState::Normal => match next_char {
 750                 Some(&'*') => state = SnippetState::InsideBulletComment,
 751                 Some(&'/') if prev_char.map_or(true, |c| c != '*') => {
 752                     state = SnippetState::InsideSingleLineComment;
 753                 }
 754                 _ => (),
 755             },
 756             '*' if state == SnippetState::InsideBulletComment &&
 757                 next_char.map_or(false, |c| *c == '/') =>
 758             {
 759                 state = SnippetState::Normal;
 760             }
 761             '\n' if state == SnippetState::InsideSingleLineComment => state = SnippetState::Normal,
 762             '"' if state == SnippetState::InsideStr && prev_char.map_or(false, |c| c != '\\') => {
 763                 state = SnippetState::Normal;
 764             }
 765             '"' if state == SnippetState::Normal && prev_char.map_or(false, |c| c != '\\') => {
 766                 state = SnippetState::InsideStr
 767             }
 768             '(' if state == SnippetState::Normal => op_parens += 1,
 769             ')' if state == SnippetState::Normal => cl_parens += 1,
 770             _ => (),
 771         }
 772         prev_char = Some(c);
 773     }
 774     op_parens.checked_sub(cl_parens).unwrap_or(0)
 775 }
 776
 777 impl Rewrite for ast::MetaItem {
 778     fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
 779         Some(match self.node {
 780             ast::MetaItemKind::Word => String::from(&*self.name.as_str()),
 781             ast::MetaItemKind::List(ref list) => {
 782                 let name = self.name.as_str();
 783                 // 3 = `#[` and `(`, 2 = `]` and `)`
 784                 let item_shape = try_opt!(
 785                     shape
 786                         .shrink_left(name.len() + 3)
 787                         .and_then(|s| s.sub_width(2))
 788                 );
 789                 let hi = self.span.hi +
 790                     BytePos(count_missing_closing_parens(&context.snippet(self.span)));
 791                 let items = itemize_list(
 792                     context.codemap,
 793                     list.iter(),
 794                     ")",
 795                     |nested_meta_item| nested_meta_item.span.lo,
 796                     // FIXME: Span from MetaItem is missing closing parens.
 797                     |nested_meta_item| {
 798                         let snippet = context.snippet(nested_meta_item.span);
 799                         nested_meta_item.span.hi + BytePos(count_missing_closing_parens(&snippet))
 800                     },
 801                     |nested_meta_item| nested_meta_item.rewrite(context, item_shape),
 802                     self.span.lo,
 803                     hi,
 804                 );
 805                 let item_vec = items.collect::<Vec<_>>();
 806                 let fmt = ListFormatting {
 807                     tactic: DefinitiveListTactic::Mixed,
 808                     separator: ",",
 809                     trailing_separator: SeparatorTactic::Never,
 810                     shape: item_shape,
 811                     ends_with_newline: false,
 812                     config: context.config,
 813                 };
 814                 format!("{}({})", name, try_opt!(write_list(&item_vec, &fmt)))
 815             }
 816             ast::MetaItemKind::NameValue(ref literal) => {
 817                 let name = self.name.as_str();
 818                 let value = context.snippet(literal.span);
 819                 if &*name == "doc" && contains_comment(&value) {
 820                     let doc_shape = Shape {
 821                         width: cmp::min(shape.width, context.config.comment_width())
 822                             .checked_sub(shape.indent.width())
 823                             .unwrap_or(0),
 824                         ..shape
 825                     };
 826                     format!(
 827                         "{}",
 828                         try_opt!(rewrite_comment(&value, false, doc_shape, context.config))
 829                     )
 830                 } else {
 831                     format!("{} = {}", name, value)
 832                 }
 833             }
 834         })
 835     }
 836 }
 837
 838 impl Rewrite for ast::Attribute {
 839     fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
 840         try_opt!(self.meta()).rewrite(context, shape).map(
 841             |rw| if rw.starts_with("///") {
 842                 rw
 843             } else {
 844                 let original = context.snippet(self.span);
 845                 if contains_comment(&original) {
 846                     original
 847                 } else {
 848                     format!("#[{}]", rw)
 849                 }
 850             },
 851         )
 852     }
 853 }
 854
 855 impl<'a> Rewrite for [ast::Attribute] {
 856     fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
 857         let mut result = String::new();
 858         if self.is_empty() {
 859             return Some(result);
 860         }
 861         let indent = shape.indent.to_string(context.config);
 862
 863         for (i, a) in self.iter().enumerate() {
 864             let a_str = try_opt!(a.rewrite(context, shape));
 865
 866             // Write comments and blank lines between attributes.
 867             if i > 0 {
 868                 let comment = context.snippet(mk_sp(self[i - 1].span.hi, a.span.lo));
 869                 // This particular horror show is to preserve line breaks in between doc
 870                 // comments. An alternative would be to force such line breaks to start
 871                 // with the usual doc comment token.
 872                 let multi_line = a_str.starts_with("//") && comment.matches('\n').count() > 1;
 873                 let comment = comment.trim();
 874                 if !comment.is_empty() {
 875                     let comment = try_opt!(rewrite_comment(
 876                         comment,
 877                         false,
 878                         Shape::legacy(
 879                             context.config.comment_width() - shape.indent.width(),
 880                             shape.indent,
 881                         ),
 882                         context.config,
 883                     ));
 884                     result.push_str(&indent);
 885                     result.push_str(&comment);
 886                     result.push('\n');
 887                 } else if multi_line {
 888                     result.push('\n');
 889                 }
 890                 result.push_str(&indent);
 891             }
 892
 893             // Write the attribute itself.
 894             result.push_str(&a_str);
 895
 896             if i < self.len() - 1 {
 897                 result.push('\n');
 898             }
 899         }
 900
 901         Some(result)
 902     }
 903 }