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.
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.
11 use syntax::attr::HasAttrs;
12 use syntax::codemap::{self, BytePos, CodeMap, Pos, Span};
13 use syntax::parse::ParseSess;
14 use syntax::{ast, visit};
17 use codemap::{LineRangeUtils, SpanUtils};
18 use comment::{CodeCharKind, CommentCodeSlices, FindUncommented};
19 use config::{BraceStyle, Config};
21 format_impl, format_trait, format_trait_alias, is_mod_decl, is_use_item,
22 rewrite_associated_impl_type, rewrite_associated_type, rewrite_existential_impl_type,
23 rewrite_existential_type, rewrite_extern_crate, rewrite_type_alias, FnSig, StaticParts,
26 use macros::{rewrite_macro, rewrite_macro_def, MacroPosition};
27 use rewrite::{Rewrite, RewriteContext};
28 use shape::{Indent, Shape};
31 self, contains_skip, count_newlines, inner_attributes, mk_sp, ptr_vec_to_ref_vec,
32 rewrite_ident, DEPR_SKIP_ANNOTATION,
34 use {ErrorKind, FormatReport, FormattingError};
36 use std::cell::RefCell;
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.
42 /// A position of the start of `big_snippet`, used as an offset.
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])
53 pub fn new(start_pos: BytePos, big_snippet: &'a str) -> Self {
54 let start_pos = start_pos.to_usize();
62 pub struct FmtVisitor<'a> {
63 pub parse_session: &'a ParseSess,
64 pub codemap: &'a CodeMap,
66 pub last_pos: BytePos,
67 // FIXME: use an RAII util or closure for indenting
68 pub block_indent: Indent,
69 pub config: &'a Config,
70 pub is_if_else_block: bool,
71 pub snippet_provider: &'a SnippetProvider<'a>,
72 pub line_number: usize,
73 pub skipped_range: Vec<(usize, usize)>,
74 pub macro_rewrite_failure: bool,
75 pub(crate) report: FormatReport,
78 impl<'b, 'a: 'b> FmtVisitor<'a> {
79 pub fn shape(&self) -> Shape {
80 Shape::indented(self.block_indent, self.config)
83 fn visit_stmt(&mut self, stmt: &ast::Stmt) {
85 "visit_stmt: {:?} {:?}",
86 self.codemap.lookup_char_pos(stmt.span.lo()),
87 self.codemap.lookup_char_pos(stmt.span.hi())
91 ast::StmtKind::Item(ref item) => {
92 self.visit_item(item);
94 ast::StmtKind::Local(..) | ast::StmtKind::Expr(..) | ast::StmtKind::Semi(..) => {
95 if contains_skip(get_attrs_from_stmt(stmt)) {
96 self.push_skipped_with_span(stmt.span());
98 let rewrite = stmt.rewrite(&self.get_context(), self.shape());
99 self.push_rewrite(stmt.span(), rewrite)
102 ast::StmtKind::Mac(ref mac) => {
103 let (ref mac, _macro_style, ref attrs) = **mac;
104 if self.visit_attrs(attrs, ast::AttrStyle::Outer) {
105 self.push_skipped_with_span(stmt.span());
107 self.visit_mac(mac, None, MacroPosition::Statement);
109 self.format_missing(stmt.span.hi());
117 inner_attrs: Option<&[ast::Attribute]>,
121 "visit_block: {:?} {:?}",
122 self.codemap.lookup_char_pos(b.span.lo()),
123 self.codemap.lookup_char_pos(b.span.hi())
126 // Check if this block has braces.
127 let brace_compensation = BytePos(if has_braces { 1 } else { 0 });
129 self.last_pos = self.last_pos + brace_compensation;
130 self.block_indent = self.block_indent.block_indent(self.config);
133 if let Some(first_stmt) = b.stmts.first() {
134 let attr_lo = inner_attrs
135 .and_then(|attrs| inner_attributes(attrs).first().map(|attr| attr.span.lo()))
137 // Attributes for an item in a statement position
138 // do not belong to the statement. (rust-lang/rust#34459)
139 if let ast::StmtKind::Item(ref item) = first_stmt.node {
142 first_stmt.attrs().first()
144 // Some stmts can have embedded attributes.
145 // e.g. `match { #![attr] ... }`
146 let attr_lo = attr.span.lo();
147 if attr_lo < first_stmt.span.lo() {
155 let snippet = self.snippet(mk_sp(
157 attr_lo.unwrap_or_else(|| first_stmt.span.lo()),
159 let len = CommentCodeSlices::new(snippet)
161 .and_then(|(kind, _, s)| {
162 if kind == CodeCharKind::Normal {
168 if let Some(len) = len {
169 self.last_pos = self.last_pos + BytePos::from_usize(len);
173 // Format inner attributes if available.
174 let skip_rewrite = if let Some(attrs) = inner_attrs {
175 self.visit_attrs(attrs, ast::AttrStyle::Inner)
181 self.push_rewrite(b.span, None);
182 self.close_block(false);
183 self.last_pos = source!(self, b.span).hi();
187 self.walk_block_stmts(b);
189 if !b.stmts.is_empty() {
190 if let Some(expr) = utils::stmt_expr(&b.stmts[b.stmts.len() - 1]) {
191 if utils::semicolon_for_expr(&self.get_context(), expr) {
197 let mut remove_len = BytePos(0);
198 if let Some(stmt) = b.stmts.last() {
199 let snippet = self.snippet(mk_sp(
201 source!(self, b.span).hi() - brace_compensation,
203 let len = CommentCodeSlices::new(snippet)
205 .and_then(|(kind, _, s)| {
206 if kind == CodeCharKind::Normal && s.trim().is_empty() {
212 if let Some(len) = len {
213 remove_len = BytePos::from_usize(len);
217 let unindent_comment = (self.is_if_else_block && !b.stmts.is_empty()) && {
218 let end_pos = source!(self, b.span).hi() - brace_compensation - remove_len;
219 let snippet = self.snippet(mk_sp(self.last_pos, end_pos));
220 snippet.contains("//") || snippet.contains("/*")
222 // FIXME: we should compress any newlines here to just one
223 if unindent_comment {
224 self.block_indent = self.block_indent.block_unindent(self.config);
226 self.format_missing_with_indent(
227 source!(self, b.span).hi() - brace_compensation - remove_len,
229 if unindent_comment {
230 self.block_indent = self.block_indent.block_indent(self.config);
232 self.close_block(unindent_comment);
233 self.last_pos = source!(self, b.span).hi();
236 // FIXME: this is a terrible hack to indent the comments between the last
237 // item in the block and the closing brace to the block's level.
238 // The closing brace itself, however, should be indented at a shallower
240 fn close_block(&mut self, unindent_comment: bool) {
241 let total_len = self.buffer.len();
242 let chars_too_many = if unindent_comment {
244 } else if self.config.hard_tabs() {
247 self.config.tab_spaces()
249 self.buffer.truncate(total_len - chars_too_many);
251 self.block_indent = self.block_indent.block_unindent(self.config);
254 // Note that this only gets called for function definitions. Required methods
255 // on traits do not get handled here.
259 generics: &ast::Generics,
262 defaultness: ast::Defaultness,
263 inner_attrs: Option<&[ast::Attribute]>,
265 let indent = self.block_indent;
267 let rewrite = match fk {
268 visit::FnKind::ItemFn(ident, _, _, b) | visit::FnKind::Method(ident, _, _, b) => {
273 &FnSig::from_fn_kind(&fk, generics, fd, defaultness),
274 mk_sp(s.lo(), b.span.lo()),
279 visit::FnKind::Closure(_) => unreachable!(),
282 if let Some(fn_str) = rewrite {
283 self.format_missing_with_indent(source!(self, s).lo());
284 self.push_str(&fn_str);
285 if let Some(c) = fn_str.chars().last() {
287 self.last_pos = source!(self, block.span).hi();
292 self.format_missing(source!(self, block.span).lo());
295 self.last_pos = source!(self, block.span).lo();
296 self.visit_block(block, inner_attrs, true)
299 pub fn visit_item(&mut self, item: &ast::Item) {
300 skip_out_of_file_lines_range_visitor!(self, item.span);
302 // This is where we bail out if there is a skip attribute. This is only
303 // complex in the module case. It is complex because the module could be
304 // in a separate file and there might be attributes in both files, but
305 // the AST lumps them all together.
307 let mut attrs = &item.attrs;
309 // For use items, skip rewriting attributes. Just check for a skip attribute.
310 ast::ItemKind::Use(..) => {
311 if contains_skip(attrs) {
312 self.push_skipped_with_span(item.span());
316 // Module is inline, in this case we treat it like any other item.
317 _ if !is_mod_decl(item) => {
318 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
319 self.push_skipped_with_span(item.span());
323 // Module is not inline, but should be skipped.
324 ast::ItemKind::Mod(..) if contains_skip(&item.attrs) => {
327 // Module is not inline and should not be skipped. We want
328 // to process only the attributes in the current file.
329 ast::ItemKind::Mod(..) => {
330 filtered_attrs = filter_inline_attrs(&item.attrs, item.span());
331 // Assert because if we should skip it should be caught by
333 assert!(!self.visit_attrs(&filtered_attrs, ast::AttrStyle::Outer));
334 attrs = &filtered_attrs;
337 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
338 self.push_skipped_with_span(item.span());
345 ast::ItemKind::Use(ref tree) => self.format_import(item, tree),
346 ast::ItemKind::Impl(..) => {
347 let snippet = self.snippet(item.span);
348 let where_span_end = snippet
349 .find_uncommented("{")
350 .map(|x| BytePos(x as u32) + source!(self, item.span).lo());
351 let rw = format_impl(&self.get_context(), item, self.block_indent, where_span_end);
352 self.push_rewrite(item.span, rw);
354 ast::ItemKind::Trait(..) => {
355 let rw = format_trait(&self.get_context(), item, self.block_indent);
356 self.push_rewrite(item.span, rw);
358 ast::ItemKind::TraitAlias(ref generics, ref generic_bounds) => {
359 let shape = Shape::indented(self.block_indent, self.config);
360 let rw = format_trait_alias(
367 self.push_rewrite(item.span, rw);
369 ast::ItemKind::ExternCrate(_) => {
370 let rw = rewrite_extern_crate(&self.get_context(), item);
371 self.push_rewrite(item.span, rw);
373 ast::ItemKind::Struct(..) | ast::ItemKind::Union(..) => {
374 self.visit_struct(&StructParts::from_item(item));
376 ast::ItemKind::Enum(ref def, ref generics) => {
377 self.format_missing_with_indent(source!(self, item.span).lo());
378 self.visit_enum(item.ident, &item.vis, def, generics, item.span);
379 self.last_pos = source!(self, item.span).hi();
381 ast::ItemKind::Mod(ref module) => {
382 let is_inline = !is_mod_decl(item);
383 self.format_missing_with_indent(source!(self, item.span).lo());
384 self.format_mod(module, &item.vis, item.span, item.ident, attrs, is_inline);
386 ast::ItemKind::Mac(ref mac) => {
387 self.visit_mac(mac, Some(item.ident), MacroPosition::Item);
389 ast::ItemKind::ForeignMod(ref foreign_mod) => {
390 self.format_missing_with_indent(source!(self, item.span).lo());
391 self.format_foreign_mod(foreign_mod, item.span);
393 ast::ItemKind::Static(..) | ast::ItemKind::Const(..) => {
394 self.visit_static(&StaticParts::from_item(item));
396 ast::ItemKind::Fn(ref decl, fn_header, ref generics, ref body) => {
397 let inner_attrs = inner_attributes(&item.attrs);
399 visit::FnKind::ItemFn(item.ident, fn_header, &item.vis, body),
403 ast::Defaultness::Final,
407 ast::ItemKind::Ty(ref ty, ref generics) => {
408 let rewrite = rewrite_type_alias(
416 self.push_rewrite(item.span, rewrite);
418 ast::ItemKind::Existential(ref generic_bounds, ref generics) => {
419 let rewrite = rewrite_existential_type(
427 self.push_rewrite(item.span, rewrite);
429 ast::ItemKind::GlobalAsm(..) => {
430 let snippet = Some(self.snippet(item.span).to_owned());
431 self.push_rewrite(item.span, snippet);
433 ast::ItemKind::MacroDef(ref def) => {
434 let rewrite = rewrite_macro_def(
443 self.push_rewrite(item.span, rewrite);
448 pub fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
449 skip_out_of_file_lines_range_visitor!(self, ti.span);
451 if self.visit_attrs(&ti.attrs, ast::AttrStyle::Outer) {
452 self.push_skipped_with_span(ti.span());
457 ast::TraitItemKind::Const(..) => self.visit_static(&StaticParts::from_trait_item(ti)),
458 ast::TraitItemKind::Method(ref sig, None) => {
459 let indent = self.block_indent;
461 self.rewrite_required_fn(indent, ti.ident, sig, &ti.generics, ti.span);
462 self.push_rewrite(ti.span, rewrite);
464 ast::TraitItemKind::Method(ref sig, Some(ref body)) => {
465 let inner_attrs = inner_attributes(&ti.attrs);
467 visit::FnKind::Method(ti.ident, sig, None, body),
471 ast::Defaultness::Final,
475 ast::TraitItemKind::Type(ref generic_bounds, ref type_default) => {
476 let rewrite = rewrite_associated_type(
478 type_default.as_ref(),
479 Some(generic_bounds),
483 self.push_rewrite(ti.span, rewrite);
485 ast::TraitItemKind::Macro(ref mac) => {
486 self.visit_mac(mac, Some(ti.ident), MacroPosition::Item);
491 pub fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
492 skip_out_of_file_lines_range_visitor!(self, ii.span);
494 if self.visit_attrs(&ii.attrs, ast::AttrStyle::Outer) {
495 self.push_skipped_with_span(ii.span());
500 ast::ImplItemKind::Method(ref sig, ref body) => {
501 let inner_attrs = inner_attributes(&ii.attrs);
503 visit::FnKind::Method(ii.ident, sig, Some(&ii.vis), body),
511 ast::ImplItemKind::Const(..) => self.visit_static(&StaticParts::from_impl_item(ii)),
512 ast::ImplItemKind::Type(ref ty) => {
513 let rewrite = rewrite_associated_impl_type(
520 self.push_rewrite(ii.span, rewrite);
522 ast::ImplItemKind::Existential(ref generic_bounds) => {
523 let rewrite = rewrite_existential_impl_type(
529 self.push_rewrite(ii.span, rewrite);
531 ast::ImplItemKind::Macro(ref mac) => {
532 self.visit_mac(mac, Some(ii.ident), MacroPosition::Item);
537 fn visit_mac(&mut self, mac: &ast::Mac, ident: Option<ast::Ident>, pos: MacroPosition) {
538 skip_out_of_file_lines_range_visitor!(self, mac.span);
541 let shape = self.shape().sub_width(1).unwrap();
542 let rewrite = self.with_context(|ctx| rewrite_macro(mac, ident, ctx, shape, pos));
543 self.push_rewrite(mac.span, rewrite);
546 pub fn push_str(&mut self, s: &str) {
547 self.line_number += count_newlines(s);
548 self.buffer.push_str(s);
551 #[cfg_attr(feature = "cargo-clippy", allow(needless_pass_by_value))]
552 fn push_rewrite_inner(&mut self, span: Span, rewrite: Option<String>) {
553 if let Some(ref s) = rewrite {
556 let snippet = self.snippet(span);
557 self.push_str(snippet);
559 self.last_pos = source!(self, span).hi();
562 pub fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
563 self.format_missing_with_indent(source!(self, span).lo());
564 self.push_rewrite_inner(span, rewrite);
567 pub fn push_skipped_with_span(&mut self, span: Span) {
568 self.format_missing_with_indent(source!(self, span).lo());
569 let lo = self.line_number + 1;
570 self.push_rewrite_inner(span, None);
571 let hi = self.line_number + 1;
572 self.skipped_range.push((lo, hi));
575 pub fn from_context(ctx: &'a RewriteContext) -> FmtVisitor<'a> {
576 FmtVisitor::from_codemap(
579 ctx.snippet_provider,
584 pub(crate) fn from_codemap(
585 parse_session: &'a ParseSess,
587 snippet_provider: &'a SnippetProvider,
588 report: FormatReport,
589 ) -> FmtVisitor<'a> {
592 codemap: parse_session.codemap(),
593 buffer: String::with_capacity(snippet_provider.big_snippet.len() * 2),
594 last_pos: BytePos(0),
595 block_indent: Indent::empty(),
597 is_if_else_block: false,
600 skipped_range: vec![],
601 macro_rewrite_failure: false,
606 pub fn opt_snippet(&'b self, span: Span) -> Option<&'a str> {
607 self.snippet_provider.span_to_snippet(span)
610 pub fn snippet(&'b self, span: Span) -> &'a str {
611 self.opt_snippet(span).unwrap()
614 // Returns true if we should skip the following item.
615 pub fn visit_attrs(&mut self, attrs: &[ast::Attribute], style: ast::AttrStyle) -> bool {
617 if attr.name() == DEPR_SKIP_ANNOTATION {
618 let file_name = self.codemap.span_to_filename(attr.span).into();
621 vec![FormattingError::from_span(
624 ErrorKind::DeprecatedAttr,
627 } else if attr.path.segments[0].ident.to_string() == "rustfmt" {
628 if attr.path.segments.len() == 1
629 || attr.path.segments[1].ident.to_string() != "skip"
631 let file_name = self.codemap.span_to_filename(attr.span).into();
634 vec![FormattingError::from_span(
643 if contains_skip(attrs) {
647 let attrs: Vec<_> = attrs.iter().filter(|a| a.style == style).cloned().collect();
648 if attrs.is_empty() {
652 let rewrite = attrs.rewrite(&self.get_context(), self.shape());
653 let span = mk_sp(attrs[0].span.lo(), attrs[attrs.len() - 1].span.hi());
654 self.push_rewrite(span, rewrite);
659 fn walk_mod_items(&mut self, m: &ast::Mod) {
660 self.visit_items_with_reordering(&ptr_vec_to_ref_vec(&m.items));
663 fn walk_stmts(&mut self, stmts: &[ast::Stmt]) {
664 fn to_stmt_item(stmt: &ast::Stmt) -> Option<&ast::Item> {
666 ast::StmtKind::Item(ref item) => Some(&**item),
671 if stmts.is_empty() {
675 // Extract leading `use ...;`.
676 let items: Vec<_> = stmts
678 .take_while(|stmt| to_stmt_item(stmt).map_or(false, is_use_item))
679 .filter_map(|stmt| to_stmt_item(stmt))
682 if items.is_empty() {
683 self.visit_stmt(&stmts[0]);
684 self.walk_stmts(&stmts[1..]);
686 self.visit_items_with_reordering(&items);
687 self.walk_stmts(&stmts[items.len()..]);
691 fn walk_block_stmts(&mut self, b: &ast::Block) {
692 self.walk_stmts(&b.stmts)
698 vis: &ast::Visibility,
701 attrs: &[ast::Attribute],
704 let vis_str = utils::format_visibility(&self.get_context(), vis);
705 self.push_str(&*vis_str);
706 self.push_str("mod ");
707 // Calling `to_owned()` to work around borrow checker.
708 let ident_str = rewrite_ident(&self.get_context(), ident).to_owned();
709 self.push_str(&ident_str);
712 match self.config.brace_style() {
713 BraceStyle::AlwaysNextLine => {
714 let indent_str = self.block_indent.to_string_with_newline(self.config);
715 self.push_str(&indent_str);
718 _ => self.push_str(" {"),
720 // Hackery to account for the closing }.
721 let mod_lo = self.snippet_provider.span_after(source!(self, s), "{");
723 self.snippet(mk_sp(mod_lo, source!(self, m.inner).hi() - BytePos(1)));
724 let body_snippet = body_snippet.trim();
725 if body_snippet.is_empty() {
728 self.last_pos = mod_lo;
729 self.block_indent = self.block_indent.block_indent(self.config);
730 self.visit_attrs(attrs, ast::AttrStyle::Inner);
731 self.walk_mod_items(m);
732 self.format_missing_with_indent(source!(self, m.inner).hi() - BytePos(1));
733 self.close_block(false);
735 self.last_pos = source!(self, m.inner).hi();
738 self.last_pos = source!(self, s).hi();
742 pub fn format_separate_mod(&mut self, m: &ast::Mod, filemap: &codemap::FileMap) {
743 self.block_indent = Indent::empty();
744 self.walk_mod_items(m);
745 self.format_missing_with_indent(filemap.end_pos);
748 pub fn skip_empty_lines(&mut self, end_pos: BytePos) {
749 while let Some(pos) = self
751 .opt_span_after(mk_sp(self.last_pos, end_pos), "\n")
753 if let Some(snippet) = self.opt_snippet(mk_sp(self.last_pos, pos)) {
754 if snippet.trim().is_empty() {
763 pub fn with_context<F>(&mut self, f: F) -> Option<String>
765 F: Fn(&RewriteContext) -> Option<String>,
768 let macro_rewrite_failure = {
769 let context = self.get_context();
770 result = f(&context);
771 unsafe { *context.macro_rewrite_failure.as_ptr() }
773 self.macro_rewrite_failure |= macro_rewrite_failure;
777 pub fn get_context(&self) -> RewriteContext {
779 parse_session: self.parse_session,
780 codemap: self.codemap,
782 inside_macro: RefCell::new(false),
783 use_block: RefCell::new(false),
784 is_if_else_block: RefCell::new(false),
785 force_one_line_chain: RefCell::new(false),
786 snippet_provider: self.snippet_provider,
787 macro_rewrite_failure: RefCell::new(false),
788 report: self.report.clone(),