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::{ast, ptr, visit};
12 use syntax::codemap::{self, CodeMap, Span, BytePos};
13 use syntax::parse::ParseSess;
15 use strings::string_buffer::StringBuffer;
19 use codemap::{LineRangeUtils, SpanUtils};
21 use rewrite::{Rewrite, RewriteContext};
22 use comment::rewrite_comment;
23 use macros::{rewrite_macro, MacroPosition};
24 use items::{rewrite_static, rewrite_associated_type, rewrite_type_alias, format_impl, format_trait};
26 fn is_use_item(item: &ast::Item) -> bool {
28 ast::ItemKind::Use(_) => true,
33 pub struct FmtVisitor<'a> {
34 pub parse_session: &'a ParseSess,
35 pub codemap: &'a CodeMap,
36 pub buffer: StringBuffer,
37 pub last_pos: BytePos,
38 // FIXME: use an RAII util or closure for indenting
39 pub block_indent: Indent,
40 pub config: &'a Config,
43 impl<'a> FmtVisitor<'a> {
44 fn visit_stmt(&mut self, stmt: &ast::Stmt) {
45 debug!("visit_stmt: {:?} {:?}",
46 self.codemap.lookup_char_pos(stmt.span.lo),
47 self.codemap.lookup_char_pos(stmt.span.hi));
49 // FIXME(#434): Move this check to somewhere more central, eg Rewrite.
50 if !self.config.file_lines.contains(&self.codemap.lookup_line_range(stmt.span)) {
55 ast::StmtKind::Item(ref item) => {
56 self.visit_item(item);
58 ast::StmtKind::Local(..) |
59 ast::StmtKind::Expr(..) |
60 ast::StmtKind::Semi(..) => {
61 let rewrite = stmt.rewrite(&self.get_context(),
62 self.config.max_width - self.block_indent.width(),
64 self.push_rewrite(stmt.span, rewrite);
66 ast::StmtKind::Mac(ref mac) => {
67 let (ref mac, _macro_style, _) = **mac;
68 self.visit_mac(mac, None, MacroPosition::Statement);
69 self.format_missing(stmt.span.hi);
74 pub fn visit_block(&mut self, b: &ast::Block) {
75 debug!("visit_block: {:?} {:?}",
76 self.codemap.lookup_char_pos(b.span.lo),
77 self.codemap.lookup_char_pos(b.span.hi));
79 // Check if this block has braces.
80 let snippet = self.snippet(b.span);
81 let has_braces = snippet.starts_with('{') || snippet.starts_with("unsafe");
82 let brace_compensation = if has_braces { BytePos(1) } else { BytePos(0) };
84 self.last_pos = self.last_pos + brace_compensation;
85 self.block_indent = self.block_indent.block_indent(self.config);
86 self.buffer.push_str("{");
88 for stmt in &b.stmts {
92 if !b.stmts.is_empty() {
93 if let Some(expr) = utils::stmt_expr(&b.stmts[b.stmts.len() - 1]) {
94 if utils::semicolon_for_expr(expr) {
95 self.buffer.push_str(";");
100 // FIXME: we should compress any newlines here to just one
101 self.format_missing_with_indent(source!(self, b.span).hi - brace_compensation);
103 self.last_pos = source!(self, b.span).hi;
106 // FIXME: this is a terrible hack to indent the comments between the last
107 // item in the block and the closing brace to the block's level.
108 // The closing brace itself, however, should be indented at a shallower
110 fn close_block(&mut self) {
111 let total_len = self.buffer.len;
112 let chars_too_many = if self.config.hard_tabs {
115 self.config.tab_spaces
117 self.buffer.truncate(total_len - chars_too_many);
118 self.buffer.push_str("}");
119 self.block_indent = self.block_indent.block_unindent(self.config);
122 // Note that this only gets called for function definitions. Required methods
123 // on traits do not get handled here.
124 fn visit_fn(&mut self,
129 defaultness: ast::Defaultness) {
130 let indent = self.block_indent;
132 let rewrite = match fk {
133 visit::FnKind::ItemFn(ident, generics, unsafety, constness, abi, vis, b) => {
135 self.rewrite_fn(indent,
144 codemap::mk_sp(s.lo, b.span.lo),
147 visit::FnKind::Method(ident, sig, vis, b) => {
149 self.rewrite_fn(indent,
157 vis.unwrap_or(&ast::Visibility::Inherited),
158 codemap::mk_sp(s.lo, b.span.lo),
161 visit::FnKind::Closure(_) => unreachable!(),
164 if let Some(fn_str) = rewrite {
165 self.format_missing_with_indent(source!(self, s).lo);
166 self.buffer.push_str(&fn_str);
167 if let Some(c) = fn_str.chars().last() {
169 self.last_pos = source!(self, block.span).hi;
174 self.format_missing(source!(self, block.span).lo);
177 self.last_pos = source!(self, block.span).lo;
178 self.visit_block(block)
181 pub fn visit_item(&mut self, item: &ast::Item) {
182 // This is where we bail out if there is a skip attribute. This is only
183 // complex in the module case. It is complex because the module could be
184 // in a separate file and there might be attributes in both files, but
185 // the AST lumps them all together.
187 ast::ItemKind::Mod(ref m) => {
188 let outer_file = self.codemap.lookup_char_pos(item.span.lo).file;
189 let inner_file = self.codemap.lookup_char_pos(m.inner.lo).file;
190 if outer_file.name == inner_file.name {
191 // Module is inline, in this case we treat modules like any
193 if self.visit_attrs(&item.attrs) {
194 self.push_rewrite(item.span, None);
197 } else if utils::contains_skip(&item.attrs) {
198 // Module is not inline, but should be skipped.
201 // Module is not inline and should not be skipped. We want
202 // to process only the attributes in the current file.
203 let attrs = item.attrs
206 let attr_file = self.codemap.lookup_char_pos(a.span.lo).file;
207 if attr_file.name == outer_file.name {
213 .collect::<Vec<_>>();
214 // Assert because if we should skip it should be caught by
216 assert!(!self.visit_attrs(&attrs));
220 if self.visit_attrs(&item.attrs) {
221 self.push_rewrite(item.span, None);
228 ast::ItemKind::Use(ref vp) => {
229 self.format_import(&item.vis, vp, item.span);
231 ast::ItemKind::Impl(..) => {
232 self.format_missing_with_indent(source!(self, item.span).lo);
233 if let Some(impl_str) = format_impl(&self.get_context(), item, self.block_indent) {
234 self.buffer.push_str(&impl_str);
235 self.last_pos = source!(self, item.span).hi;
238 ast::ItemKind::Trait(..) => {
239 self.format_missing_with_indent(item.span.lo);
240 if let Some(trait_str) = format_trait(&self.get_context(),
243 self.buffer.push_str(&trait_str);
244 self.last_pos = source!(self, item.span).hi;
247 ast::ItemKind::ExternCrate(_) => {
248 self.format_missing_with_indent(source!(self, item.span).lo);
249 let new_str = self.snippet(item.span);
250 self.buffer.push_str(&new_str);
251 self.last_pos = source!(self, item.span).hi;
253 ast::ItemKind::Struct(ref def, ref generics) => {
255 let indent = self.block_indent;
256 let context = self.get_context();
257 ::items::format_struct(&context,
266 .map(|s| match *def {
267 ast::VariantData::Tuple(..) => s + ";",
271 self.push_rewrite(item.span, rewrite);
273 ast::ItemKind::Enum(ref def, ref generics) => {
274 self.format_missing_with_indent(source!(self, item.span).lo);
275 self.visit_enum(item.ident, &item.vis, def, generics, item.span);
276 self.last_pos = source!(self, item.span).hi;
278 ast::ItemKind::Mod(ref module) => {
279 self.format_missing_with_indent(source!(self, item.span).lo);
280 self.format_mod(module, &item.vis, item.span, item.ident);
282 ast::ItemKind::Mac(ref mac) => {
283 self.visit_mac(mac, Some(item.ident), MacroPosition::Item);
285 ast::ItemKind::ForeignMod(ref foreign_mod) => {
286 self.format_missing_with_indent(source!(self, item.span).lo);
287 self.format_foreign_mod(foreign_mod, item.span);
289 ast::ItemKind::Static(ref ty, mutability, ref expr) => {
290 let rewrite = rewrite_static("static",
296 &self.get_context());
297 self.push_rewrite(item.span, rewrite);
299 ast::ItemKind::Const(ref ty, ref expr) => {
300 let rewrite = rewrite_static("const",
304 ast::Mutability::Immutable,
306 &self.get_context());
307 self.push_rewrite(item.span, rewrite);
309 ast::ItemKind::DefaultImpl(..) => {
310 // FIXME(#78): format impl definitions.
312 ast::ItemKind::Fn(ref decl, unsafety, constness, abi, ref generics, ref body) => {
313 self.visit_fn(visit::FnKind::ItemFn(item.ident,
323 ast::Defaultness::Final)
325 ast::ItemKind::Ty(ref ty, ref generics) => {
326 let rewrite = rewrite_type_alias(&self.get_context(),
333 self.push_rewrite(item.span, rewrite);
335 ast::ItemKind::Union(..) => {
336 // FIXME(#1157): format union definitions.
341 pub fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
342 if self.visit_attrs(&ti.attrs) {
343 self.push_rewrite(ti.span, None);
348 ast::TraitItemKind::Const(ref ty, ref expr_opt) => {
349 let rewrite = rewrite_static("const",
350 &ast::Visibility::Inherited,
353 ast::Mutability::Immutable,
355 &self.get_context());
356 self.push_rewrite(ti.span, rewrite);
358 ast::TraitItemKind::Method(ref sig, None) => {
359 let indent = self.block_indent;
360 let rewrite = self.rewrite_required_fn(indent, ti.ident, sig, ti.span);
361 self.push_rewrite(ti.span, rewrite);
363 ast::TraitItemKind::Method(ref sig, Some(ref body)) => {
364 self.visit_fn(visit::FnKind::Method(ti.ident, sig, None, body),
368 ast::Defaultness::Final);
370 ast::TraitItemKind::Type(ref type_param_bounds, _) => {
371 let rewrite = rewrite_associated_type(ti.ident,
373 Some(type_param_bounds),
376 self.push_rewrite(ti.span, rewrite);
378 ast::TraitItemKind::Macro(..) => {
379 // FIXME(#1158) Macros in trait item position
384 pub fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
385 if self.visit_attrs(&ii.attrs) {
386 self.push_rewrite(ii.span, None);
391 ast::ImplItemKind::Method(ref sig, ref body) => {
392 self.visit_fn(visit::FnKind::Method(ii.ident, sig, Some(&ii.vis), body),
398 ast::ImplItemKind::Const(ref ty, ref expr) => {
399 let rewrite = rewrite_static("const",
403 ast::Mutability::Immutable,
405 &self.get_context());
406 self.push_rewrite(ii.span, rewrite);
408 ast::ImplItemKind::Type(ref ty) => {
409 let rewrite = rewrite_associated_type(ii.ident,
414 self.push_rewrite(ii.span, rewrite);
416 ast::ImplItemKind::Macro(ref mac) => {
417 self.visit_mac(mac, Some(ii.ident), MacroPosition::Item);
422 fn visit_mac(&mut self, mac: &ast::Mac, ident: Option<ast::Ident>, pos: MacroPosition) {
424 let width = self.config.max_width - self.block_indent.width() - 1;
425 let rewrite = rewrite_macro(mac,
431 self.push_rewrite(mac.span, rewrite);
434 fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
435 self.format_missing_with_indent(source!(self, span).lo);
436 let result = rewrite.unwrap_or_else(|| self.snippet(span));
437 self.buffer.push_str(&result);
438 self.last_pos = source!(self, span).hi;
441 pub fn from_codemap(parse_session: &'a ParseSess, config: &'a Config) -> FmtVisitor<'a> {
443 parse_session: parse_session,
444 codemap: parse_session.codemap(),
445 buffer: StringBuffer::new(),
446 last_pos: BytePos(0),
447 block_indent: Indent {
455 pub fn snippet(&self, span: Span) -> String {
456 match self.codemap.span_to_snippet(span) {
459 println!("Couldn't make snippet for span {:?}->{:?}",
460 self.codemap.lookup_char_pos(span.lo),
461 self.codemap.lookup_char_pos(span.hi));
467 // Returns true if we should skip the following item.
468 pub fn visit_attrs(&mut self, attrs: &[ast::Attribute]) -> bool {
469 if utils::contains_skip(attrs) {
473 let outers: Vec<_> = attrs.iter()
474 .filter(|a| a.style == ast::AttrStyle::Outer)
477 if outers.is_empty() {
481 let first = &outers[0];
482 self.format_missing_with_indent(source!(self, first.span).lo);
484 let rewrite = outers.rewrite(&self.get_context(),
485 self.config.max_width - self.block_indent.width(),
488 self.buffer.push_str(&rewrite);
489 let last = outers.last().unwrap();
490 self.last_pos = source!(self, last.span).hi;
494 fn walk_mod_items(&mut self, m: &ast::Mod) {
495 let mut items_left: &[ptr::P<ast::Item>] = &m.items;
496 while !items_left.is_empty() {
497 // If the next item is a `use` declaration, then extract it and any subsequent `use`s
498 // to be potentially reordered within `format_imports`. Otherwise, just format the
499 // next item for output.
500 if self.config.reorder_imports && is_use_item(&*items_left[0]) {
501 let use_item_length =
502 items_left.iter().take_while(|ppi| is_use_item(&***ppi)).count();
503 let (use_items, rest) = items_left.split_at(use_item_length);
504 self.format_imports(use_items);
507 // `unwrap()` is safe here because we know `items_left`
508 // has elements from the loop condition
509 let (item, rest) = items_left.split_first().unwrap();
510 self.visit_item(item);
516 fn format_mod(&mut self, m: &ast::Mod, vis: &ast::Visibility, s: Span, ident: ast::Ident) {
517 // Decide whether this is an inline mod or an external mod.
518 let local_file_name = self.codemap.span_to_filename(s);
519 let inner_span = source!(self, m.inner);
520 let is_internal = !(inner_span.lo.0 == 0 && inner_span.hi.0 == 0) &&
521 local_file_name == self.codemap.span_to_filename(inner_span);
523 self.buffer.push_str(&*utils::format_visibility(vis));
524 self.buffer.push_str("mod ");
525 self.buffer.push_str(&ident.to_string());
528 self.buffer.push_str(" {");
529 // Hackery to account for the closing }.
530 let mod_lo = self.codemap.span_after(source!(self, s), "{");
532 self.snippet(codemap::mk_sp(mod_lo, source!(self, m.inner).hi - BytePos(1)));
533 let body_snippet = body_snippet.trim();
534 if body_snippet.is_empty() {
535 self.buffer.push_str("}");
537 self.last_pos = mod_lo;
538 self.block_indent = self.block_indent.block_indent(self.config);
539 self.walk_mod_items(m);
540 self.format_missing_with_indent(source!(self, m.inner).hi - BytePos(1));
543 self.last_pos = source!(self, m.inner).hi;
545 self.buffer.push_str(";");
546 self.last_pos = source!(self, s).hi;
550 pub fn format_separate_mod(&mut self, m: &ast::Mod) {
551 let filemap = self.codemap.lookup_char_pos(source!(self, m.inner).lo).file;
552 self.last_pos = filemap.start_pos;
553 self.block_indent = Indent::empty();
554 self.walk_mod_items(m);
555 self.format_missing_with_indent(filemap.end_pos);
558 pub fn get_context(&self) -> RewriteContext {
560 parse_session: self.parse_session,
561 codemap: self.codemap,
563 block_indent: self.block_indent,
568 impl<'a> Rewrite for [ast::Attribute] {
569 fn rewrite(&self, context: &RewriteContext, _: usize, offset: Indent) -> Option<String> {
570 let mut result = String::new();
574 let indent = offset.to_string(context.config);
576 for (i, a) in self.iter().enumerate() {
577 let mut a_str = context.snippet(a.span);
579 // Write comments and blank lines between attributes.
581 let comment = context.snippet(codemap::mk_sp(self[i - 1].span.hi, a.span.lo));
582 // This particular horror show is to preserve line breaks in between doc
583 // comments. An alternative would be to force such line breaks to start
584 // with the usual doc comment token.
585 let multi_line = a_str.starts_with("//") && comment.matches('\n').count() > 1;
586 let comment = comment.trim();
587 if !comment.is_empty() {
588 let comment = try_opt!(rewrite_comment(comment,
590 context.config.ideal_width -
594 result.push_str(&indent);
595 result.push_str(&comment);
597 } else if multi_line {
600 result.push_str(&indent);
603 if a_str.starts_with("//") {
604 a_str = try_opt!(rewrite_comment(&a_str,
606 context.config.ideal_width - offset.width(),
611 // Write the attribute itself.
612 result.push_str(&a_str);
614 if i < self.len() - 1 {