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_extern_crate,
23 rewrite_type_alias, FnSig, StaticParts, StructParts,
25 use macros::{rewrite_macro, rewrite_macro_def, MacroPosition};
26 use rewrite::{Rewrite, RewriteContext};
27 use shape::{Indent, Shape};
29 use utils::{self, contains_skip, count_newlines, inner_attributes, mk_sp, ptr_vec_to_ref_vec};
31 use std::cell::RefCell;
33 /// Creates a string slice corresponding to the specified span.
34 pub struct SnippetProvider<'a> {
35 /// A pointer to the content of the file we are formatting.
37 /// A position of the start of `big_snippet`, used as an offset.
41 impl<'a> SnippetProvider<'a> {
42 pub fn span_to_snippet(&self, span: Span) -> Option<&str> {
43 let start_index = span.lo().to_usize().checked_sub(self.start_pos)?;
44 let end_index = span.hi().to_usize().checked_sub(self.start_pos)?;
45 Some(&self.big_snippet[start_index..end_index])
48 pub fn new(start_pos: BytePos, big_snippet: &'a str) -> Self {
49 let start_pos = start_pos.to_usize();
57 pub struct FmtVisitor<'a> {
58 pub parse_session: &'a ParseSess,
59 pub codemap: &'a CodeMap,
61 pub last_pos: BytePos,
62 // FIXME: use an RAII util or closure for indenting
63 pub block_indent: Indent,
64 pub config: &'a Config,
65 pub is_if_else_block: bool,
66 pub snippet_provider: &'a SnippetProvider<'a>,
67 pub line_number: usize,
68 pub skipped_range: Vec<(usize, usize)>,
71 impl<'b, 'a: 'b> FmtVisitor<'a> {
72 pub fn shape(&self) -> Shape {
73 Shape::indented(self.block_indent, self.config)
76 fn visit_stmt(&mut self, stmt: &ast::Stmt) {
78 "visit_stmt: {:?} {:?}",
79 self.codemap.lookup_char_pos(stmt.span.lo()),
80 self.codemap.lookup_char_pos(stmt.span.hi())
84 ast::StmtKind::Item(ref item) => {
85 self.visit_item(item);
87 ast::StmtKind::Local(..) | ast::StmtKind::Expr(..) | ast::StmtKind::Semi(..) => {
88 if contains_skip(get_attrs_from_stmt(stmt)) {
89 self.push_skipped_with_span(stmt.span());
91 let rewrite = stmt.rewrite(&self.get_context(), self.shape());
92 self.push_rewrite(stmt.span(), rewrite)
95 ast::StmtKind::Mac(ref mac) => {
96 let (ref mac, _macro_style, ref attrs) = **mac;
97 if self.visit_attrs(attrs, ast::AttrStyle::Outer) {
98 self.push_skipped_with_span(stmt.span());
100 self.visit_mac(mac, None, MacroPosition::Statement);
102 self.format_missing(stmt.span.hi());
110 inner_attrs: Option<&[ast::Attribute]>,
114 "visit_block: {:?} {:?}",
115 self.codemap.lookup_char_pos(b.span.lo()),
116 self.codemap.lookup_char_pos(b.span.hi())
119 // Check if this block has braces.
120 let brace_compensation = BytePos(if has_braces { 1 } else { 0 });
122 self.last_pos = self.last_pos + brace_compensation;
123 self.block_indent = self.block_indent.block_indent(self.config);
126 if self.config.remove_blank_lines_at_start_or_end_of_block() {
127 if let Some(first_stmt) = b.stmts.first() {
128 let attr_lo = inner_attrs
129 .and_then(|attrs| inner_attributes(attrs).first().map(|attr| attr.span.lo()))
131 // Attributes for an item in a statement position
132 // do not belong to the statement. (rust-lang/rust#34459)
133 if let ast::StmtKind::Item(ref item) = first_stmt.node {
136 first_stmt.attrs().first()
138 // Some stmts can have embedded attributes.
139 // e.g. `match { #![attr] ... }`
140 let attr_lo = attr.span.lo();
141 if attr_lo < first_stmt.span.lo() {
149 let snippet = self.snippet(mk_sp(
151 attr_lo.unwrap_or_else(|| first_stmt.span.lo()),
153 let len = CommentCodeSlices::new(snippet)
155 .and_then(|(kind, _, s)| {
156 if kind == CodeCharKind::Normal {
162 if let Some(len) = len {
163 self.last_pos = self.last_pos + BytePos::from_usize(len);
168 // Format inner attributes if available.
169 let skip_rewrite = if let Some(attrs) = inner_attrs {
170 self.visit_attrs(attrs, ast::AttrStyle::Inner)
176 self.push_rewrite(b.span, None);
177 self.close_block(false);
178 self.last_pos = source!(self, b.span).hi();
182 self.walk_block_stmts(b);
184 if !b.stmts.is_empty() {
185 if let Some(expr) = utils::stmt_expr(&b.stmts[b.stmts.len() - 1]) {
186 if utils::semicolon_for_expr(&self.get_context(), expr) {
192 let mut remove_len = BytePos(0);
193 if self.config.remove_blank_lines_at_start_or_end_of_block() {
194 if let Some(stmt) = b.stmts.last() {
195 let snippet = self.snippet(mk_sp(
197 source!(self, b.span).hi() - brace_compensation,
199 let len = CommentCodeSlices::new(snippet)
201 .and_then(|(kind, _, s)| {
202 if kind == CodeCharKind::Normal && s.trim().is_empty() {
208 if let Some(len) = len {
209 remove_len = BytePos::from_usize(len);
214 let unindent_comment = (self.is_if_else_block && !b.stmts.is_empty()) && {
215 let end_pos = source!(self, b.span).hi() - brace_compensation - remove_len;
216 let snippet = self.snippet(mk_sp(self.last_pos, end_pos));
217 snippet.contains("//") || snippet.contains("/*")
219 // FIXME: we should compress any newlines here to just one
220 if unindent_comment {
221 self.block_indent = self.block_indent.block_unindent(self.config);
223 self.format_missing_with_indent(
224 source!(self, b.span).hi() - brace_compensation - remove_len,
226 if unindent_comment {
227 self.block_indent = self.block_indent.block_indent(self.config);
229 self.close_block(unindent_comment);
230 self.last_pos = source!(self, b.span).hi();
233 // FIXME: this is a terrible hack to indent the comments between the last
234 // item in the block and the closing brace to the block's level.
235 // The closing brace itself, however, should be indented at a shallower
237 fn close_block(&mut self, unindent_comment: bool) {
238 let total_len = self.buffer.len();
239 let chars_too_many = if unindent_comment {
241 } else if self.config.hard_tabs() {
244 self.config.tab_spaces()
246 self.buffer.truncate(total_len - chars_too_many);
248 self.block_indent = self.block_indent.block_unindent(self.config);
251 // Note that this only gets called for function definitions. Required methods
252 // on traits do not get handled here.
256 generics: &ast::Generics,
259 defaultness: ast::Defaultness,
260 inner_attrs: Option<&[ast::Attribute]>,
262 let indent = self.block_indent;
264 let rewrite = match fk {
265 visit::FnKind::ItemFn(ident, _, _, _, _, b) | visit::FnKind::Method(ident, _, _, b) => {
270 &FnSig::from_fn_kind(&fk, generics, fd, defaultness),
271 mk_sp(s.lo(), b.span.lo()),
276 visit::FnKind::Closure(_) => unreachable!(),
279 if let Some(fn_str) = rewrite {
280 self.format_missing_with_indent(source!(self, s).lo());
281 self.push_str(&fn_str);
282 if let Some(c) = fn_str.chars().last() {
284 self.last_pos = source!(self, block.span).hi();
289 self.format_missing(source!(self, block.span).lo());
292 self.last_pos = source!(self, block.span).lo();
293 self.visit_block(block, inner_attrs, true)
296 pub fn visit_item(&mut self, item: &ast::Item) {
297 skip_out_of_file_lines_range_visitor!(self, item.span);
299 // This is where we bail out if there is a skip attribute. This is only
300 // complex in the module case. It is complex because the module could be
301 // in a separate file and there might be attributes in both files, but
302 // the AST lumps them all together.
304 let mut attrs = &item.attrs;
306 // Module is inline, in this case we treat it like any other item.
307 _ if !is_mod_decl(item) => {
308 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
309 self.push_skipped_with_span(item.span());
313 // Module is not inline, but should be skipped.
314 ast::ItemKind::Mod(..) if contains_skip(&item.attrs) => {
317 // Module is not inline and should not be skipped. We want
318 // to process only the attributes in the current file.
319 ast::ItemKind::Mod(..) => {
320 filtered_attrs = filter_inline_attrs(&item.attrs, item.span());
321 // Assert because if we should skip it should be caught by
323 assert!(!self.visit_attrs(&filtered_attrs, ast::AttrStyle::Outer));
324 attrs = &filtered_attrs;
327 if self.visit_attrs(&item.attrs, ast::AttrStyle::Outer) {
328 self.push_skipped_with_span(item.span());
335 ast::ItemKind::Use(ref tree) => self.format_import(item, tree),
336 ast::ItemKind::Impl(..) => {
337 let snippet = self.snippet(item.span);
338 let where_span_end = snippet
339 .find_uncommented("{")
340 .map(|x| BytePos(x as u32) + source!(self, item.span).lo());
341 let rw = format_impl(&self.get_context(), item, self.block_indent, where_span_end);
342 self.push_rewrite(item.span, rw);
344 ast::ItemKind::Trait(..) => {
345 let rw = format_trait(&self.get_context(), item, self.block_indent);
346 self.push_rewrite(item.span, rw);
348 ast::ItemKind::TraitAlias(ref generics, ref ty_param_bounds) => {
349 let shape = Shape::indented(self.block_indent, self.config);
350 let rw = format_trait_alias(
357 self.push_rewrite(item.span, rw);
359 ast::ItemKind::ExternCrate(_) => {
360 let rw = rewrite_extern_crate(&self.get_context(), item);
361 self.push_rewrite(item.span, rw);
363 ast::ItemKind::Struct(..) | ast::ItemKind::Union(..) => {
364 self.visit_struct(&StructParts::from_item(item));
366 ast::ItemKind::Enum(ref def, ref generics) => {
367 self.format_missing_with_indent(source!(self, item.span).lo());
368 self.visit_enum(item.ident, &item.vis, def, generics, item.span);
369 self.last_pos = source!(self, item.span).hi();
371 ast::ItemKind::Mod(ref module) => {
372 let is_inline = !is_mod_decl(item);
373 self.format_missing_with_indent(source!(self, item.span).lo());
374 self.format_mod(module, &item.vis, item.span, item.ident, attrs, is_inline);
376 ast::ItemKind::Mac(ref mac) => {
377 self.visit_mac(mac, Some(item.ident), MacroPosition::Item);
379 ast::ItemKind::ForeignMod(ref foreign_mod) => {
380 self.format_missing_with_indent(source!(self, item.span).lo());
381 self.format_foreign_mod(foreign_mod, item.span);
383 ast::ItemKind::Static(..) | ast::ItemKind::Const(..) => {
384 self.visit_static(&StaticParts::from_item(item));
386 ast::ItemKind::Fn(ref decl, unsafety, constness, abi, ref generics, ref body) => {
387 let inner_attrs = inner_attributes(&item.attrs);
389 visit::FnKind::ItemFn(item.ident, unsafety, constness, abi, &item.vis, body),
393 ast::Defaultness::Final,
397 ast::ItemKind::Ty(ref ty, ref generics) => {
398 let rewrite = rewrite_type_alias(
407 self.push_rewrite(item.span, rewrite);
409 ast::ItemKind::GlobalAsm(..) => {
410 let snippet = Some(self.snippet(item.span).to_owned());
411 self.push_rewrite(item.span, snippet);
413 ast::ItemKind::MacroDef(ref def) => {
414 let rewrite = rewrite_macro_def(
423 self.push_rewrite(item.span, rewrite);
428 pub fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
429 skip_out_of_file_lines_range_visitor!(self, ti.span);
431 if self.visit_attrs(&ti.attrs, ast::AttrStyle::Outer) {
432 self.push_skipped_with_span(ti.span());
437 ast::TraitItemKind::Const(..) => self.visit_static(&StaticParts::from_trait_item(ti)),
438 ast::TraitItemKind::Method(ref sig, None) => {
439 let indent = self.block_indent;
441 self.rewrite_required_fn(indent, ti.ident, sig, &ti.generics, ti.span);
442 self.push_rewrite(ti.span, rewrite);
444 ast::TraitItemKind::Method(ref sig, Some(ref body)) => {
445 let inner_attrs = inner_attributes(&ti.attrs);
447 visit::FnKind::Method(ti.ident, sig, None, body),
451 ast::Defaultness::Final,
455 ast::TraitItemKind::Type(ref type_param_bounds, ref type_default) => {
456 let rewrite = rewrite_associated_type(
458 type_default.as_ref(),
459 Some(type_param_bounds),
463 self.push_rewrite(ti.span, rewrite);
465 ast::TraitItemKind::Macro(ref mac) => {
466 self.visit_mac(mac, Some(ti.ident), MacroPosition::Item);
471 pub fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
472 skip_out_of_file_lines_range_visitor!(self, ii.span);
474 if self.visit_attrs(&ii.attrs, ast::AttrStyle::Outer) {
475 self.push_skipped_with_span(ii.span());
480 ast::ImplItemKind::Method(ref sig, ref body) => {
481 let inner_attrs = inner_attributes(&ii.attrs);
483 visit::FnKind::Method(ii.ident, sig, Some(&ii.vis), body),
491 ast::ImplItemKind::Const(..) => self.visit_static(&StaticParts::from_impl_item(ii)),
492 ast::ImplItemKind::Type(ref ty) => {
493 let rewrite = rewrite_associated_impl_type(
501 self.push_rewrite(ii.span, rewrite);
503 ast::ImplItemKind::Macro(ref mac) => {
504 self.visit_mac(mac, Some(ii.ident), MacroPosition::Item);
509 fn visit_mac(&mut self, mac: &ast::Mac, ident: Option<ast::Ident>, pos: MacroPosition) {
510 skip_out_of_file_lines_range_visitor!(self, mac.span);
513 let shape = self.shape().sub_width(1).unwrap();
514 let rewrite = rewrite_macro(mac, ident, &self.get_context(), shape, pos);
515 self.push_rewrite(mac.span, rewrite);
518 pub fn push_str(&mut self, s: &str) {
519 self.line_number += count_newlines(s);
520 self.buffer.push_str(s);
523 #[cfg_attr(feature = "cargo-clippy", allow(needless_pass_by_value))]
524 fn push_rewrite_inner(&mut self, span: Span, rewrite: Option<String>) {
525 if let Some(ref s) = rewrite {
528 let snippet = self.snippet(span);
529 self.push_str(snippet);
531 self.last_pos = source!(self, span).hi();
534 pub fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
535 self.format_missing_with_indent(source!(self, span).lo());
536 self.push_rewrite_inner(span, rewrite);
539 pub fn push_skipped_with_span(&mut self, span: Span) {
540 self.format_missing_with_indent(source!(self, span).lo());
541 let lo = self.line_number + 1;
542 self.push_rewrite_inner(span, None);
543 let hi = self.line_number + 1;
544 self.skipped_range.push((lo, hi));
547 pub fn from_context(ctx: &'a RewriteContext) -> FmtVisitor<'a> {
548 FmtVisitor::from_codemap(ctx.parse_session, ctx.config, ctx.snippet_provider)
552 parse_session: &'a ParseSess,
554 snippet_provider: &'a SnippetProvider,
555 ) -> FmtVisitor<'a> {
558 codemap: parse_session.codemap(),
559 buffer: String::with_capacity(snippet_provider.big_snippet.len() * 2),
560 last_pos: BytePos(0),
561 block_indent: Indent::empty(),
563 is_if_else_block: false,
566 skipped_range: vec![],
570 pub fn opt_snippet(&'b self, span: Span) -> Option<&'a str> {
571 self.snippet_provider.span_to_snippet(span)
574 pub fn snippet(&'b self, span: Span) -> &'a str {
575 self.opt_snippet(span).unwrap()
578 // Returns true if we should skip the following item.
579 pub fn visit_attrs(&mut self, attrs: &[ast::Attribute], style: ast::AttrStyle) -> bool {
580 if contains_skip(attrs) {
584 let attrs: Vec<_> = attrs.iter().filter(|a| a.style == style).cloned().collect();
585 if attrs.is_empty() {
589 let rewrite = attrs.rewrite(&self.get_context(), self.shape());
590 let span = mk_sp(attrs[0].span.lo(), attrs[attrs.len() - 1].span.hi());
591 self.push_rewrite(span, rewrite);
596 fn walk_mod_items(&mut self, m: &ast::Mod) {
597 self.visit_items_with_reordering(&ptr_vec_to_ref_vec(&m.items));
600 fn walk_stmts(&mut self, stmts: &[ast::Stmt]) {
601 fn to_stmt_item(stmt: &ast::Stmt) -> Option<&ast::Item> {
603 ast::StmtKind::Item(ref item) => Some(&**item),
608 if stmts.is_empty() {
612 // Extract leading `use ...;`.
613 let items: Vec<_> = stmts
615 .take_while(|stmt| to_stmt_item(stmt).map_or(false, is_use_item))
616 .filter_map(|stmt| to_stmt_item(stmt))
619 if items.is_empty() {
620 self.visit_stmt(&stmts[0]);
621 self.walk_stmts(&stmts[1..]);
623 self.visit_items_with_reordering(&items);
624 self.walk_stmts(&stmts[items.len()..]);
628 fn walk_block_stmts(&mut self, b: &ast::Block) {
629 self.walk_stmts(&b.stmts)
635 vis: &ast::Visibility,
638 attrs: &[ast::Attribute],
641 self.push_str(&*utils::format_visibility(vis));
642 self.push_str("mod ");
643 self.push_str(&ident.to_string());
646 match self.config.brace_style() {
647 BraceStyle::AlwaysNextLine => {
648 let indent_str = self.block_indent.to_string_with_newline(self.config);
649 self.push_str(&indent_str);
652 _ => self.push_str(" {"),
654 // Hackery to account for the closing }.
655 let mod_lo = self.snippet_provider.span_after(source!(self, s), "{");
657 self.snippet(mk_sp(mod_lo, source!(self, m.inner).hi() - BytePos(1)));
658 let body_snippet = body_snippet.trim();
659 if body_snippet.is_empty() {
662 self.last_pos = mod_lo;
663 self.block_indent = self.block_indent.block_indent(self.config);
664 self.visit_attrs(attrs, ast::AttrStyle::Inner);
665 self.walk_mod_items(m);
666 self.format_missing_with_indent(source!(self, m.inner).hi() - BytePos(1));
667 self.close_block(false);
669 self.last_pos = source!(self, m.inner).hi();
672 self.last_pos = source!(self, s).hi();
676 pub fn format_separate_mod(&mut self, m: &ast::Mod, filemap: &codemap::FileMap) {
677 self.block_indent = Indent::empty();
678 self.walk_mod_items(m);
679 self.format_missing_with_indent(filemap.end_pos);
682 pub fn skip_empty_lines(&mut self, end_pos: BytePos) {
683 while let Some(pos) = self.snippet_provider
684 .opt_span_after(mk_sp(self.last_pos, end_pos), "\n")
686 if let Some(snippet) = self.opt_snippet(mk_sp(self.last_pos, pos)) {
687 if snippet.trim().is_empty() {
696 pub fn get_context(&self) -> RewriteContext {
698 parse_session: self.parse_session,
699 codemap: self.codemap,
701 inside_macro: RefCell::new(false),
702 use_block: RefCell::new(false),
703 is_if_else_block: RefCell::new(false),
704 force_one_line_chain: RefCell::new(false),
705 snippet_provider: self.snippet_provider,