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::parse::ParseSess;
  13 use syntax::source_map::{self, BytePos, Pos, SourceMap, Span};
  14 use syntax::{ast, visit};
  15
  16 use attr::*;
  17 use comment::{CodeCharKind, CommentCodeSlices, FindUncommented};
  18 use config::{BraceStyle, Config};
  19 use items::{
  20     format_impl, format_trait, format_trait_alias, is_mod_decl, is_use_item,
  21     rewrite_associated_impl_type, rewrite_associated_type, rewrite_existential_impl_type,
  22     rewrite_existential_type, rewrite_extern_crate, rewrite_type_alias, FnSig, StaticParts,
  23     StructParts,
  24 };
  25 use macros::{rewrite_macro, rewrite_macro_def, MacroPosition};
  26 use rewrite::{Rewrite, RewriteContext};
  27 use shape::{Indent, Shape};
  28 use source_map::{LineRangeUtils, SpanUtils};
  29 use spanned::Spanned;
  30 use utils::{
  31     self, contains_skip, count_newlines, inner_attributes, mk_sp, ptr_vec_to_ref_vec,
  32     rewrite_ident, DEPR_SKIP_ANNOTATION,
  33 };
  34 use {ErrorKind, FormatReport, FormattingError};
  35
  36 use std::cell::RefCell;
  37
  38 /// Creates a string slice corresponding to the specified span.
  39 pub struct SnippetProvider<'a> {
  40     /// A pointer to the content of the file we are formatting.
  41     big_snippet: &'a str,
  42     /// A position of the start of `big_snippet`, used as an offset.
  43     start_pos: usize,
  44 }
  45
  46 impl<'a> SnippetProvider<'a> {
  47     pub fn span_to_snippet(&self, span: Span) -> Option<&str> {
  48         let start_index = span.lo().to_usize().checked_sub(self.start_pos)?;
  49         let end_index = span.hi().to_usize().checked_sub(self.start_pos)?;
  50         Some(&self.big_snippet[start_index..end_index])
  51     }
  52
  53     pub fn new(start_pos: BytePos, big_snippet: &'a str) -> Self {
  54         let start_pos = start_pos.to_usize();
  55         SnippetProvider {
  56             big_snippet,
  57             start_pos,
  58         }
  59     }
  60 }
  61
  62 pub struct FmtVisitor<'a> {
  63     parent_context: Option<&'a RewriteContext<'a>>,
  64     pub parse_session: &'a ParseSess,
  65     pub source_map: &'a SourceMap,
  66     pub buffer: String,
  67     pub last_pos: BytePos,
  68     // FIXME: use an RAII util or closure for indenting
  69     pub block_indent: Indent,
  70     pub config: &'a Config,
  71     pub is_if_else_block: bool,
  72     pub snippet_provider: &'a SnippetProvider<'a>,
  73     pub line_number: usize,
  74     pub skipped_range: Vec<(usize, usize)>,
  75     pub macro_rewrite_failure: bool,
  76     pub(crate) report: FormatReport,
  77 }
  78
  79 impl<'a> Drop for FmtVisitor<'a> {
  80     fn drop(&mut self) {
  81         if let Some(ctx) = self.parent_context {
  82             if self.macro_rewrite_failure {
  83                 ctx.macro_rewrite_failure.replace(true);
  84             }
  85         }
  86     }
  87 }
  88
  89 impl<'b, 'a: 'b> FmtVisitor<'a> {
  90     fn set_parent_context(&mut self, context: &'a RewriteContext) {
  91         self.parent_context = Some(context);
  92     }
  93
  94     pub fn shape(&self) -> Shape {
  95         Shape::indented(self.block_indent, self.config)
  96     }
  97
  98     fn visit_stmt(&mut self, stmt: &ast::Stmt) {
  99         debug!(
 100             "visit_stmt: {:?} {:?}",
 101             self.source_map.lookup_char_pos(stmt.span.lo()),
 102             self.source_map.lookup_char_pos(stmt.span.hi())
 103         );
 104
 105         match stmt.node {
 106             ast::StmtKind::Item(ref item) => {
 107                 self.visit_item(item);
 108                 // Handle potential `;` after the item.
 109                 self.format_missing(stmt.span.hi());
 110             }
 111             ast::StmtKind::Local(..) | ast::StmtKind::Expr(..) | ast::StmtKind::Semi(..) => {
 112                 if contains_skip(get_attrs_from_stmt(stmt)) {
 113                     self.push_skipped_with_span(stmt.span());
 114                 } else {
 115                     let shape = self.shape().clone();
 116                     let rewrite = self.with_context(|ctx| stmt.rewrite(&ctx, shape));
 117                     self.push_rewrite(stmt.span(), rewrite)
 118                 }
 119             }
 120             ast::StmtKind::Mac(ref mac) => {
 121                 let (ref mac, _macro_style, ref attrs) = **mac;
 122                 if self.visit_attrs(attrs, ast::AttrStyle::Outer) {
 123                     self.push_skipped_with_span(stmt.span());
 124                 } else {
 125                     self.visit_mac(mac, None, MacroPosition::Statement);
 126                 }
 127                 self.format_missing(stmt.span.hi());
 128             }
 129         }
 130     }
 131
 132     pub fn visit_block(
 133         &mut self,
 134         b: &ast::Block,
 135         inner_attrs: Option<&[ast::Attribute]>,
 136         has_braces: bool,
 137     ) {
 138         debug!(
 139             "visit_block: {:?} {:?}",
 140             self.source_map.lookup_char_pos(b.span.lo()),
 141             self.source_map.lookup_char_pos(b.span.hi())
 142         );
 143
 144         // Check if this block has braces.
 145         let brace_compensation = BytePos(if has_braces { 1 } else { 0 });
 146
 147         self.last_pos = self.last_pos + brace_compensation;
 148         self.block_indent = self.block_indent.block_indent(self.config);
 149         self.push_str("{");
 150
 151         if let Some(first_stmt) = b.stmts.first() {
 152             let attr_lo = inner_attrs
 153                 .and_then(|attrs| inner_attributes(attrs).first().map(|attr| attr.span.lo()))
 154                 .or_else(|| {
 155                     // Attributes for an item in a statement position
 156                     // do not belong to the statement. (rust-lang/rust#34459)
 157                     if let ast::StmtKind::Item(ref item) = first_stmt.node {
 158                         item.attrs.first()
 159                     } else {
 160                         first_stmt.attrs().first()
 161                     }
 162                     .and_then(|attr| {
 163                         // Some stmts can have embedded attributes.
 164                         // e.g. `match { #![attr] ... }`
 165                         let attr_lo = attr.span.lo();
 166                         if attr_lo < first_stmt.span.lo() {
 167                             Some(attr_lo)
 168                         } else {
 169                             None
 170                         }
 171                     })
 172                 });
 173
 174             let snippet = self.snippet(mk_sp(
 175                 self.last_pos,
 176                 attr_lo.unwrap_or_else(|| first_stmt.span.lo()),
 177             ));
 178             let len = CommentCodeSlices::new(snippet)
 179                 .nth(0)
 180                 .and_then(|(kind, _, s)| {
 181                     if kind == CodeCharKind::Normal {
 182                         s.rfind('\n')
 183                     } else {
 184                         None
 185                     }
 186                 });
 187             if let Some(len) = len {
 188                 self.last_pos = self.last_pos + BytePos::from_usize(len);
 189             }
 190         }
 191
 192         // Format inner attributes if available.
 193         let skip_rewrite = if let Some(attrs) = inner_attrs {
 194             self.visit_attrs(attrs, ast::AttrStyle::Inner)
 195         } else {
 196             false
 197         };
 198
 199         if skip_rewrite {
 200             self.push_rewrite(b.span, None);
 201             self.close_block(false);
 202             self.last_pos = source!(self, b.span).hi();
 203             return;
 204         }
 205
 206         self.walk_block_stmts(b);
 207
 208         if !b.stmts.is_empty() {
 209             if let Some(expr) = utils::stmt_expr(&b.stmts[b.stmts.len() - 1]) {
 210                 if utils::semicolon_for_expr(&self.get_context(), expr) {
 211                     self.push_str(";");
 212                 }
 213             }
 214         }
 215
 216         let mut remove_len = BytePos(0);
 217         if let Some(stmt) = b.stmts.last() {
 218             let snippet = self.snippet(mk_sp(
 219                 stmt.span.hi(),
 220                 source!(self, b.span).hi() - brace_compensation,
 221             ));
 222             let len = CommentCodeSlices::new(snippet)
 223                 .last()
 224                 .and_then(|(kind, _, s)| {
 225                     if kind == CodeCharKind::Normal && s.trim().is_empty() {
 226                         Some(s.len())
 227                     } else {
 228                         None
 229                     }
 230                 });
 231             if let Some(len) = len {
 232                 remove_len = BytePos::from_usize(len);
 233             }
 234         }
 235
 236         let unindent_comment = (self.is_if_else_block && !b.stmts.is_empty()) && {
 237             let end_pos = source!(self, b.span).hi() - brace_compensation - remove_len;
 238             let snippet = self.snippet(mk_sp(self.last_pos, end_pos));
 239             snippet.contains("//") || snippet.contains("/*")
 240         };
 241         // FIXME: we should compress any newlines here to just one
 242         if unindent_comment {
 243             self.block_indent = self.block_indent.block_unindent(self.config);
 244         }
 245         self.format_missing_with_indent(
 246             source!(self, b.span).hi() - brace_compensation - remove_len,
 247         );
 248         if unindent_comment {
 249             self.block_indent = self.block_indent.block_indent(self.config);
 250         }
 251         self.close_block(unindent_comment);
 252         self.last_pos = source!(self, b.span).hi();
 253     }
 254
 255     // FIXME: this is a terrible hack to indent the comments between the last
 256     // item in the block and the closing brace to the block's level.
 257     // The closing brace itself, however, should be indented at a shallower
 258     // level.
 259     fn close_block(&mut self, unindent_comment: bool) {
 260         let total_len = self.buffer.len();
 261         let chars_too_many = if unindent_comment {
 262             0
 263         } else if self.config.hard_tabs() {
 264             1
 265         } else {
 266             self.config.tab_spaces()
 267         };
 268         self.buffer.truncate(total_len - chars_too_many);
 269         self.push_str("}");
 270         self.block_indent = self.block_indent.block_unindent(self.config);
 271     }
 272
 273     // Note that this only gets called for function definitions. Required methods
 274     // on traits do not get handled here.
 275     fn visit_fn(
 276         &mut self,
 277         fk: visit::FnKind,
 278         generics: &ast::Generics,
 279         fd: &ast::FnDecl,
 280         s: Span,
 281         defaultness: ast::Defaultness,
 282         inner_attrs: Option<&[ast::Attribute]>,
 283     ) {
 284         let indent = self.block_indent;
 285         let block;
 286         let rewrite = match fk {
 287             visit::FnKind::ItemFn(ident, _, _, b) | visit::FnKind::Method(ident, _, _, b) => {
 288                 block = b;
 289                 self.rewrite_fn(
 290                     indent,
 291                     ident,
 292                     &FnSig::from_fn_kind(&fk, generics, fd, defaultness),
 293                     mk_sp(s.lo(), b.span.lo()),
 294                     b,
 295                     inner_attrs,
 296                 )
 297             }
 298             visit::FnKind::Closure(_) => unreachable!(),
 299         };
 300
 301         if let Some(fn_str) = rewrite {
 302             self.format_missing_with_indent(source!(self, s).lo());
 303             self.push_str(&fn_str);
 304             if let Some(c) = fn_str.chars().last() {
 305                 if c == '}' {
 306                     self.last_pos = source!(self, block.span).hi();
 307                     return;
 308                 }
 309             }
 310         } else {
 311             self.format_missing(source!(self, block.span).lo());
 312         }
 313
 314         self.last_pos = source!(self, block.span).lo();
 315         self.visit_block(block, inner_attrs, true)
 316     }
 317
 318     pub fn visit_item(&mut self, item: &ast::Item) {
 319         skip_out_of_file_lines_range_visitor!(self, item.span);
 320
 321         // This is where we bail out if there is a skip attribute. This is only
 322         // complex in the module case. It is complex because the module could be
 323         // in a separate file and there might be attributes in both files, but
 324         // the AST lumps them all together.
 325         let filtered_attrs;
 326         let mut attrs = &item.attrs;
 327         match item.node {
 328             // For use items, skip rewriting attributes. Just check for a skip attribute.
 329             ast::ItemKind::Use(..) => {
 330                 if contains_skip(attrs) {
 331                     self.push_skipped_with_span(item.span());
 332                     return;
 333                 }
 334             }
 335             // Module is inline, in this case we treat it like any other item.
 336             _ if !is_mod_decl(item) => {
 337                 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
 338                     self.push_skipped_with_span(item.span());
 339                     return;
 340                 }
 341             }
 342             // Module is not inline, but should be skipped.
 343             ast::ItemKind::Mod(..) if contains_skip(&item.attrs) => {
 344                 return;
 345             }
 346             // Module is not inline and should not be skipped. We want
 347             // to process only the attributes in the current file.
 348             ast::ItemKind::Mod(..) => {
 349                 filtered_attrs = filter_inline_attrs(&item.attrs, item.span());
 350                 // Assert because if we should skip it should be caught by
 351                 // the above case.
 352                 assert!(!self.visit_attrs(&filtered_attrs, ast::AttrStyle::Outer));
 353                 attrs = &filtered_attrs;
 354             }
 355             _ => {
 356                 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
 357                     self.push_skipped_with_span(item.span());
 358                     return;
 359                 }
 360             }
 361         }
 362
 363         match item.node {
 364             ast::ItemKind::Use(ref tree) => self.format_import(item, tree),
 365             ast::ItemKind::Impl(..) => {
 366                 let snippet = self.snippet(item.span);
 367                 let where_span_end = snippet
 368                     .find_uncommented("{")
 369                     .map(|x| BytePos(x as u32) + source!(self, item.span).lo());
 370                 let block_indent = self.block_indent.clone();
 371                 let rw =
 372                     self.with_context(|ctx| format_impl(&ctx, item, block_indent, where_span_end));
 373                 self.push_rewrite(item.span, rw);
 374             }
 375             ast::ItemKind::Trait(..) => {
 376                 let block_indent = self.block_indent.clone();
 377                 let rw = self.with_context(|ctx| format_trait(&ctx, item, block_indent));
 378                 self.push_rewrite(item.span, rw);
 379             }
 380             ast::ItemKind::TraitAlias(ref generics, ref generic_bounds) => {
 381                 let shape = Shape::indented(self.block_indent, self.config);
 382                 let rw = format_trait_alias(
 383                     &self.get_context(),
 384                     item.ident,
 385                     generics,
 386                     generic_bounds,
 387                     shape,
 388                 );
 389                 self.push_rewrite(item.span, rw);
 390             }
 391             ast::ItemKind::ExternCrate(_) => {
 392                 let rw = rewrite_extern_crate(&self.get_context(), item);
 393                 self.push_rewrite(item.span, rw);
 394             }
 395             ast::ItemKind::Struct(..) | ast::ItemKind::Union(..) => {
 396                 self.visit_struct(&StructParts::from_item(item));
 397             }
 398             ast::ItemKind::Enum(ref def, ref generics) => {
 399                 self.format_missing_with_indent(source!(self, item.span).lo());
 400                 self.visit_enum(item.ident, &item.vis, def, generics, item.span);
 401                 self.last_pos = source!(self, item.span).hi();
 402             }
 403             ast::ItemKind::Mod(ref module) => {
 404                 let is_inline = !is_mod_decl(item);
 405                 self.format_missing_with_indent(source!(self, item.span).lo());
 406                 self.format_mod(module, &item.vis, item.span, item.ident, attrs, is_inline);
 407             }
 408             ast::ItemKind::Mac(ref mac) => {
 409                 self.visit_mac(mac, Some(item.ident), MacroPosition::Item);
 410             }
 411             ast::ItemKind::ForeignMod(ref foreign_mod) => {
 412                 self.format_missing_with_indent(source!(self, item.span).lo());
 413                 self.format_foreign_mod(foreign_mod, item.span);
 414             }
 415             ast::ItemKind::Static(..) | ast::ItemKind::Const(..) => {
 416                 self.visit_static(&StaticParts::from_item(item));
 417             }
 418             ast::ItemKind::Fn(ref decl, fn_header, ref generics, ref body) => {
 419                 let inner_attrs = inner_attributes(&item.attrs);
 420                 self.visit_fn(
 421                     visit::FnKind::ItemFn(item.ident, fn_header, &item.vis, body),
 422                     generics,
 423                     decl,
 424                     item.span,
 425                     ast::Defaultness::Final,
 426                     Some(&inner_attrs),
 427                 )
 428             }
 429             ast::ItemKind::Ty(ref ty, ref generics) => {
 430                 let rewrite = rewrite_type_alias(
 431                     &self.get_context(),
 432                     self.block_indent,
 433                     item.ident,
 434                     ty,
 435                     generics,
 436                     &item.vis,
 437                 );
 438                 self.push_rewrite(item.span, rewrite);
 439             }
 440             ast::ItemKind::Existential(ref generic_bounds, ref generics) => {
 441                 let rewrite = rewrite_existential_type(
 442                     &self.get_context(),
 443                     self.block_indent,
 444                     item.ident,
 445                     generic_bounds,
 446                     generics,
 447                     &item.vis,
 448                 );
 449                 self.push_rewrite(item.span, rewrite);
 450             }
 451             ast::ItemKind::GlobalAsm(..) => {
 452                 let snippet = Some(self.snippet(item.span).to_owned());
 453                 self.push_rewrite(item.span, snippet);
 454             }
 455             ast::ItemKind::MacroDef(ref def) => {
 456                 let rewrite = rewrite_macro_def(
 457                     &self.get_context(),
 458                     self.shape(),
 459                     self.block_indent,
 460                     def,
 461                     item.ident,
 462                     &item.vis,
 463                     item.span,
 464                 );
 465                 self.push_rewrite(item.span, rewrite);
 466             }
 467         }
 468     }
 469
 470     pub fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
 471         skip_out_of_file_lines_range_visitor!(self, ti.span);
 472
 473         if self.visit_attrs(&ti.attrs, ast::AttrStyle::Outer) {
 474             self.push_skipped_with_span(ti.span());
 475             return;
 476         }
 477
 478         match ti.node {
 479             ast::TraitItemKind::Const(..) => self.visit_static(&StaticParts::from_trait_item(ti)),
 480             ast::TraitItemKind::Method(ref sig, None) => {
 481                 let indent = self.block_indent;
 482                 let rewrite =
 483                     self.rewrite_required_fn(indent, ti.ident, sig, &ti.generics, ti.span);
 484                 self.push_rewrite(ti.span, rewrite);
 485             }
 486             ast::TraitItemKind::Method(ref sig, Some(ref body)) => {
 487                 let inner_attrs = inner_attributes(&ti.attrs);
 488                 self.visit_fn(
 489                     visit::FnKind::Method(ti.ident, sig, None, body),
 490                     &ti.generics,
 491                     &sig.decl,
 492                     ti.span,
 493                     ast::Defaultness::Final,
 494                     Some(&inner_attrs),
 495                 );
 496             }
 497             ast::TraitItemKind::Type(ref generic_bounds, ref type_default) => {
 498                 let rewrite = rewrite_associated_type(
 499                     ti.ident,
 500                     type_default.as_ref(),
 501                     &ti.generics,
 502                     Some(generic_bounds),
 503                     &self.get_context(),
 504                     self.block_indent,
 505                 );
 506                 self.push_rewrite(ti.span, rewrite);
 507             }
 508             ast::TraitItemKind::Macro(ref mac) => {
 509                 self.visit_mac(mac, Some(ti.ident), MacroPosition::Item);
 510             }
 511         }
 512     }
 513
 514     pub fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
 515         skip_out_of_file_lines_range_visitor!(self, ii.span);
 516
 517         if self.visit_attrs(&ii.attrs, ast::AttrStyle::Outer) {
 518             self.push_skipped_with_span(ii.span());
 519             return;
 520         }
 521
 522         match ii.node {
 523             ast::ImplItemKind::Method(ref sig, ref body) => {
 524                 let inner_attrs = inner_attributes(&ii.attrs);
 525                 self.visit_fn(
 526                     visit::FnKind::Method(ii.ident, sig, Some(&ii.vis), body),
 527                     &ii.generics,
 528                     &sig.decl,
 529                     ii.span,
 530                     ii.defaultness,
 531                     Some(&inner_attrs),
 532                 );
 533             }
 534             ast::ImplItemKind::Const(..) => self.visit_static(&StaticParts::from_impl_item(ii)),
 535             ast::ImplItemKind::Type(ref ty) => {
 536                 let rewrite = rewrite_associated_impl_type(
 537                     ii.ident,
 538                     ii.defaultness,
 539                     Some(ty),
 540                     &ii.generics,
 541                     &self.get_context(),
 542                     self.block_indent,
 543                 );
 544                 self.push_rewrite(ii.span, rewrite);
 545             }
 546             ast::ImplItemKind::Existential(ref generic_bounds) => {
 547                 let rewrite = rewrite_existential_impl_type(
 548                     &self.get_context(),
 549                     ii.ident,
 550                     &ii.generics,
 551                     generic_bounds,
 552                     self.block_indent,
 553                 );
 554                 self.push_rewrite(ii.span, rewrite);
 555             }
 556             ast::ImplItemKind::Macro(ref mac) => {
 557                 self.visit_mac(mac, Some(ii.ident), MacroPosition::Item);
 558             }
 559         }
 560     }
 561
 562     fn visit_mac(&mut self, mac: &ast::Mac, ident: Option<ast::Ident>, pos: MacroPosition) {
 563         skip_out_of_file_lines_range_visitor!(self, mac.span);
 564
 565         // 1 = ;
 566         let shape = self.shape().sub_width(1).unwrap();
 567         let rewrite = self.with_context(|ctx| rewrite_macro(mac, ident, ctx, shape, pos));
 568         self.push_rewrite(mac.span, rewrite);
 569     }
 570
 571     pub fn push_str(&mut self, s: &str) {
 572         self.line_number += count_newlines(s);
 573         self.buffer.push_str(s);
 574     }
 575
 576     #[cfg_attr(feature = "cargo-clippy", allow(needless_pass_by_value))]
 577     fn push_rewrite_inner(&mut self, span: Span, rewrite: Option<String>) {
 578         if let Some(ref s) = rewrite {
 579             self.push_str(s);
 580         } else {
 581             let snippet = self.snippet(span);
 582             self.push_str(snippet);
 583         }
 584         self.last_pos = source!(self, span).hi();
 585     }
 586
 587     pub fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
 588         self.format_missing_with_indent(source!(self, span).lo());
 589         self.push_rewrite_inner(span, rewrite);
 590     }
 591
 592     pub fn push_skipped_with_span(&mut self, span: Span) {
 593         self.format_missing_with_indent(source!(self, span).lo());
 594         let lo = self.line_number + 1;
 595         self.push_rewrite_inner(span, None);
 596         let hi = self.line_number + 1;
 597         self.skipped_range.push((lo, hi));
 598     }
 599
 600     pub fn from_context(ctx: &'a RewriteContext) -> FmtVisitor<'a> {
 601         let mut visitor = FmtVisitor::from_source_map(
 602             ctx.parse_session,
 603             ctx.config,
 604             ctx.snippet_provider,
 605             ctx.report.clone(),
 606         );
 607         visitor.set_parent_context(ctx);
 608         visitor
 609     }
 610
 611     pub(crate) fn from_source_map(
 612         parse_session: &'a ParseSess,
 613         config: &'a Config,
 614         snippet_provider: &'a SnippetProvider,
 615         report: FormatReport,
 616     ) -> FmtVisitor<'a> {
 617         FmtVisitor {
 618             parent_context: None,
 619             parse_session,
 620             source_map: parse_session.source_map(),
 621             buffer: String::with_capacity(snippet_provider.big_snippet.len() * 2),
 622             last_pos: BytePos(0),
 623             block_indent: Indent::empty(),
 624             config,
 625             is_if_else_block: false,
 626             snippet_provider,
 627             line_number: 0,
 628             skipped_range: vec![],
 629             macro_rewrite_failure: false,
 630             report,
 631         }
 632     }
 633
 634     pub fn opt_snippet(&'b self, span: Span) -> Option<&'a str> {
 635         self.snippet_provider.span_to_snippet(span)
 636     }
 637
 638     pub fn snippet(&'b self, span: Span) -> &'a str {
 639         self.opt_snippet(span).unwrap()
 640     }
 641
 642     // Returns true if we should skip the following item.
 643     pub fn visit_attrs(&mut self, attrs: &[ast::Attribute], style: ast::AttrStyle) -> bool {
 644         for attr in attrs {
 645             if attr.name() == DEPR_SKIP_ANNOTATION {
 646                 let file_name = self.source_map.span_to_filename(attr.span).into();
 647                 self.report.append(
 648                     file_name,
 649                     vec![FormattingError::from_span(
 650                         attr.span,
 651                         &self.source_map,
 652                         ErrorKind::DeprecatedAttr,
 653                     )],
 654                 );
 655             } else if attr.path.segments[0].ident.to_string() == "rustfmt" {
 656                 if attr.path.segments.len() == 1
 657                     || attr.path.segments[1].ident.to_string() != "skip"
 658                 {
 659                     let file_name = self.source_map.span_to_filename(attr.span).into();
 660                     self.report.append(
 661                         file_name,
 662                         vec![FormattingError::from_span(
 663                             attr.span,
 664                             &self.source_map,
 665                             ErrorKind::BadAttr,
 666                         )],
 667                     );
 668                 }
 669             }
 670         }
 671         if contains_skip(attrs) {
 672             return true;
 673         }
 674
 675         let attrs: Vec<_> = attrs.iter().filter(|a| a.style == style).cloned().collect();
 676         if attrs.is_empty() {
 677             return false;
 678         }
 679
 680         let rewrite = attrs.rewrite(&self.get_context(), self.shape());
 681         let span = mk_sp(attrs[0].span.lo(), attrs[attrs.len() - 1].span.hi());
 682         self.push_rewrite(span, rewrite);
 683
 684         false
 685     }
 686
 687     fn walk_mod_items(&mut self, m: &ast::Mod) {
 688         self.visit_items_with_reordering(&ptr_vec_to_ref_vec(&m.items));
 689     }
 690
 691     fn walk_stmts(&mut self, stmts: &[ast::Stmt]) {
 692         fn to_stmt_item(stmt: &ast::Stmt) -> Option<&ast::Item> {
 693             match stmt.node {
 694                 ast::StmtKind::Item(ref item) => Some(&**item),
 695                 _ => None,
 696             }
 697         }
 698
 699         if stmts.is_empty() {
 700             return;
 701         }
 702
 703         // Extract leading `use ...;`.
 704         let items: Vec<_> = stmts
 705             .iter()
 706             .take_while(|stmt| to_stmt_item(stmt).map_or(false, is_use_item))
 707             .filter_map(|stmt| to_stmt_item(stmt))
 708             .collect();
 709
 710         if items.is_empty() {
 711             self.visit_stmt(&stmts[0]);
 712             self.walk_stmts(&stmts[1..]);
 713         } else {
 714             self.visit_items_with_reordering(&items);
 715             self.walk_stmts(&stmts[items.len()..]);
 716         }
 717     }
 718
 719     fn walk_block_stmts(&mut self, b: &ast::Block) {
 720         self.walk_stmts(&b.stmts)
 721     }
 722
 723     fn format_mod(
 724         &mut self,
 725         m: &ast::Mod,
 726         vis: &ast::Visibility,
 727         s: Span,
 728         ident: ast::Ident,
 729         attrs: &[ast::Attribute],
 730         is_internal: bool,
 731     ) {
 732         let vis_str = utils::format_visibility(&self.get_context(), vis);
 733         self.push_str(&*vis_str);
 734         self.push_str("mod ");
 735         // Calling `to_owned()` to work around borrow checker.
 736         let ident_str = rewrite_ident(&self.get_context(), ident).to_owned();
 737         self.push_str(&ident_str);
 738
 739         if is_internal {
 740             match self.config.brace_style() {
 741                 BraceStyle::AlwaysNextLine => {
 742                     let indent_str = self.block_indent.to_string_with_newline(self.config);
 743                     self.push_str(&indent_str);
 744                     self.push_str("{");
 745                 }
 746                 _ => self.push_str(" {"),
 747             }
 748             // Hackery to account for the closing }.
 749             let mod_lo = self.snippet_provider.span_after(source!(self, s), "{");
 750             let body_snippet =
 751                 self.snippet(mk_sp(mod_lo, source!(self, m.inner).hi() - BytePos(1)));
 752             let body_snippet = body_snippet.trim();
 753             if body_snippet.is_empty() {
 754                 self.push_str("}");
 755             } else {
 756                 self.last_pos = mod_lo;
 757                 self.block_indent = self.block_indent.block_indent(self.config);
 758                 self.visit_attrs(attrs, ast::AttrStyle::Inner);
 759                 self.walk_mod_items(m);
 760                 self.format_missing_with_indent(source!(self, m.inner).hi() - BytePos(1));
 761                 self.close_block(false);
 762             }
 763             self.last_pos = source!(self, m.inner).hi();
 764         } else {
 765             self.push_str(";");
 766             self.last_pos = source!(self, s).hi();
 767         }
 768     }
 769
 770     pub fn format_separate_mod(&mut self, m: &ast::Mod, source_file: &source_map::SourceFile) {
 771         self.block_indent = Indent::empty();
 772         self.walk_mod_items(m);
 773         self.format_missing_with_indent(source_file.end_pos);
 774     }
 775
 776     pub fn skip_empty_lines(&mut self, end_pos: BytePos) {
 777         while let Some(pos) = self
 778             .snippet_provider
 779             .opt_span_after(mk_sp(self.last_pos, end_pos), "\n")
 780         {
 781             if let Some(snippet) = self.opt_snippet(mk_sp(self.last_pos, pos)) {
 782                 if snippet.trim().is_empty() {
 783                     self.last_pos = pos;
 784                 } else {
 785                     return;
 786                 }
 787             }
 788         }
 789     }
 790
 791     pub fn with_context<F>(&mut self, f: F) -> Option<String>
 792     where
 793         F: Fn(&RewriteContext) -> Option<String>,
 794     {
 795         let result;
 796         let macro_rewrite_failure = {
 797             let context = self.get_context();
 798             result = f(&context);
 799             unsafe { *context.macro_rewrite_failure.as_ptr() }
 800         };
 801         self.macro_rewrite_failure |= macro_rewrite_failure;
 802         result
 803     }
 804
 805     pub fn get_context(&self) -> RewriteContext {
 806         RewriteContext {
 807             parse_session: self.parse_session,
 808             source_map: self.source_map,
 809             config: self.config,
 810             inside_macro: RefCell::new(false),
 811             use_block: RefCell::new(false),
 812             is_if_else_block: RefCell::new(false),
 813             force_one_line_chain: RefCell::new(false),
 814             snippet_provider: self.snippet_provider,
 815             macro_rewrite_failure: RefCell::new(false),
 816             report: self.report.clone(),
 817         }
 818     }
 819 }