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.
12 use syntax::codemap::{self, CodeMap, Span, BytePos};
13 use syntax::parse::ParseSess;
16 use strings::string_buffer::StringBuffer;
18 use {Indent, WriteMode};
21 use rewrite::{Rewrite, RewriteContext};
22 use comment::rewrite_comment;
23 use macros::rewrite_macro;
24 use items::{rewrite_static, rewrite_type_alias, format_impl};
26 pub struct FmtVisitor<'a> {
27 pub parse_session: &'a ParseSess,
28 pub codemap: &'a CodeMap,
29 pub buffer: StringBuffer,
30 pub last_pos: BytePos,
31 // FIXME: use an RAII util or closure for indenting
32 pub block_indent: Indent,
33 pub config: &'a Config,
34 pub write_mode: Option<WriteMode>,
37 impl<'a> FmtVisitor<'a> {
38 fn visit_stmt(&mut self, stmt: &ast::Stmt) {
40 ast::Stmt_::StmtDecl(ref decl, _) => {
41 if let ast::Decl_::DeclItem(ref item) = decl.node {
42 self.visit_item(item);
44 let rewrite = stmt.rewrite(&self.get_context(),
45 self.config.max_width - self.block_indent.width(),
48 self.push_rewrite(stmt.span, rewrite);
51 ast::Stmt_::StmtExpr(..) | ast::Stmt_::StmtSemi(..) => {
52 let rewrite = stmt.rewrite(&self.get_context(),
53 self.config.max_width - self.block_indent.width(),
56 self.push_rewrite(stmt.span, rewrite);
58 ast::Stmt_::StmtMac(ref mac, _macro_style, _) => {
59 self.format_missing_with_indent(stmt.span.lo);
65 pub fn visit_block(&mut self, b: &ast::Block) {
66 debug!("visit_block: {:?} {:?}",
67 self.codemap.lookup_char_pos(b.span.lo),
68 self.codemap.lookup_char_pos(b.span.hi));
70 // Check if this block has braces.
71 let snippet = self.snippet(b.span);
72 let has_braces = snippet.starts_with("{") || snippet.starts_with("unsafe");
73 let brace_compensation = if has_braces {
79 self.last_pos = self.last_pos + brace_compensation;
80 self.block_indent = self.block_indent.block_indent(self.config);
81 self.buffer.push_str("{");
83 for stmt in &b.stmts {
84 self.visit_stmt(&stmt)
87 if let Some(ref e) = b.expr {
88 self.format_missing_with_indent(e.span.lo);
89 let rewrite = e.rewrite(&self.get_context(),
90 self.config.max_width - self.block_indent.width(),
92 .unwrap_or_else(|| self.snippet(e.span));
94 self.buffer.push_str(&rewrite);
95 self.last_pos = e.span.hi;
97 if utils::semicolon_for_expr(e) {
98 self.buffer.push_str(";");
102 // FIXME: we should compress any newlines here to just one
103 self.format_missing_with_indent(b.span.hi - brace_compensation);
105 self.last_pos = b.span.hi;
108 // FIXME: this is a terrible hack to indent the comments between the last
109 // item in the block and the closing brace to the block's level.
110 // The closing brace itself, however, should be indented at a shallower
112 fn close_block(&mut self) {
113 let total_len = self.buffer.len;
114 let chars_too_many = if self.config.hard_tabs {
117 self.config.tab_spaces
119 self.buffer.truncate(total_len - chars_too_many);
120 self.buffer.push_str("}");
121 self.block_indent = self.block_indent.block_unindent(self.config);
124 // Note that this only gets called for function definitions. Required methods
125 // on traits do not get handled here.
126 fn visit_fn(&mut self,
132 let indent = self.block_indent;
133 let rewrite = match fk {
134 visit::FnKind::ItemFn(ident, ref generics, unsafety, constness, abi, vis) => {
135 self.rewrite_fn(indent,
144 codemap::mk_sp(s.lo, b.span.lo),
147 visit::FnKind::Method(ident, ref sig, vis) => {
148 self.rewrite_fn(indent,
151 Some(&sig.explicit_self),
156 vis.unwrap_or(ast::Visibility::Inherited),
157 codemap::mk_sp(s.lo, b.span.lo),
160 visit::FnKind::Closure => None,
163 if let Some(fn_str) = rewrite {
164 self.format_missing_with_indent(s.lo);
165 self.buffer.push_str(&fn_str);
166 if let Some(c) = fn_str.chars().last() {
168 self.last_pos = b.span.hi;
173 self.format_missing(b.span.lo);
176 self.last_pos = b.span.lo;
180 fn visit_item(&mut self, item: &ast::Item) {
181 // Don't look at attributes for modules (except for rustfmt_skip).
182 // We want to avoid looking at attributes in another file, which the AST
183 // doesn't distinguish.
184 // FIXME This is overly conservative and means we miss attributes on
187 ast::Item_::ItemMod(_) => {
188 if utils::contains_skip(&item.attrs) {
193 if self.visit_attrs(&item.attrs) {
194 self.push_rewrite(item.span, None);
201 ast::Item_::ItemUse(ref vp) => {
202 self.format_import(item.vis, vp, item.span);
204 ast::Item_::ItemImpl(..) => {
205 self.format_missing_with_indent(item.span.lo);
206 if let Some(impl_str) = format_impl(&self.get_context(), item, self.block_indent) {
207 self.buffer.push_str(&impl_str);
208 self.last_pos = item.span.hi;
211 // FIXME(#78): format traits.
212 ast::Item_::ItemTrait(_, _, _, ref trait_items) => {
213 self.format_missing_with_indent(item.span.lo);
214 self.block_indent = self.block_indent.block_indent(self.config);
215 for item in trait_items {
216 self.visit_trait_item(&item);
218 self.block_indent = self.block_indent.block_unindent(self.config);
220 ast::Item_::ItemExternCrate(_) => {
221 self.format_missing_with_indent(item.span.lo);
222 let new_str = self.snippet(item.span);
223 self.buffer.push_str(&new_str);
224 self.last_pos = item.span.hi;
226 ast::Item_::ItemStruct(ref def, ref generics) => {
228 let indent = self.block_indent;
229 let context = self.get_context();
230 ::items::format_struct(&context,
240 ast::VariantData::Tuple(..) => s + ";",
245 self.push_rewrite(item.span, rewrite);
247 ast::Item_::ItemEnum(ref def, ref generics) => {
248 self.format_missing_with_indent(item.span.lo);
249 self.visit_enum(item.ident, item.vis, def, generics, item.span);
250 self.last_pos = item.span.hi;
252 ast::Item_::ItemMod(ref module) => {
253 self.format_missing_with_indent(item.span.lo);
254 self.format_mod(module, item.vis, item.span, item.ident);
256 ast::Item_::ItemMac(..) => {
257 self.format_missing_with_indent(item.span.lo);
258 let snippet = self.snippet(item.span);
259 self.buffer.push_str(&snippet);
260 self.last_pos = item.span.hi;
261 // FIXME: we cannot format these yet, because of a bad span.
262 // See rust lang issue #28424.
264 ast::Item_::ItemForeignMod(ref foreign_mod) => {
265 self.format_missing_with_indent(item.span.lo);
266 self.format_foreign_mod(foreign_mod, item.span);
268 ast::Item_::ItemStatic(ref ty, mutability, ref expr) => {
269 let rewrite = rewrite_static("static",
275 &self.get_context());
276 self.push_rewrite(item.span, rewrite);
278 ast::Item_::ItemConst(ref ty, ref expr) => {
279 let rewrite = rewrite_static("const",
283 ast::Mutability::MutImmutable,
285 &self.get_context());
286 self.push_rewrite(item.span, rewrite);
288 ast::Item_::ItemDefaultImpl(..) => {
289 // FIXME(#78): format impl definitions.
291 ast::ItemFn(ref declaration, unsafety, constness, abi, ref generics, ref body) => {
292 self.visit_fn(visit::FnKind::ItemFn(item.ident,
303 ast::Item_::ItemTy(ref ty, ref generics) => {
304 let rewrite = rewrite_type_alias(&self.get_context(),
311 self.push_rewrite(item.span, rewrite);
316 fn visit_trait_item(&mut self, ti: &ast::TraitItem) {
317 if self.visit_attrs(&ti.attrs) {
322 ast::ConstTraitItem(..) => {
325 ast::MethodTraitItem(ref sig, None) => {
326 let indent = self.block_indent;
327 let rewrite = self.rewrite_required_fn(indent, ti.ident, sig, ti.span);
328 self.push_rewrite(ti.span, rewrite);
330 ast::MethodTraitItem(ref sig, Some(ref body)) => {
331 self.visit_fn(visit::FnKind::Method(ti.ident, sig, None),
337 ast::TypeTraitItem(..) => {
343 pub fn visit_impl_item(&mut self, ii: &ast::ImplItem) {
344 if self.visit_attrs(&ii.attrs) {
349 ast::ImplItemKind::Method(ref sig, ref body) => {
350 self.visit_fn(visit::FnKind::Method(ii.ident, sig, Some(ii.vis)),
356 ast::ImplItemKind::Const(..) => {
359 ast::ImplItemKind::Type(_) => {
362 ast::ImplItemKind::Macro(ref mac) => {
363 self.format_missing_with_indent(ii.span.lo);
369 fn visit_mac(&mut self, mac: &ast::Mac) {
371 let width = self.config.max_width - self.block_indent.width() - 1;
372 let rewrite = rewrite_macro(mac, &self.get_context(), width, self.block_indent);
374 if let Some(res) = rewrite {
375 self.buffer.push_str(&res);
376 self.last_pos = mac.span.hi;
380 fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
381 self.format_missing_with_indent(span.lo);
382 let result = rewrite.unwrap_or_else(|| self.snippet(span));
383 self.buffer.push_str(&result);
384 self.last_pos = span.hi;
387 pub fn from_codemap(parse_session: &'a ParseSess,
389 mode: Option<WriteMode>)
392 parse_session: parse_session,
393 codemap: parse_session.codemap(),
394 buffer: StringBuffer::new(),
395 last_pos: BytePos(0),
396 block_indent: Indent {
405 pub fn snippet(&self, span: Span) -> String {
406 match self.codemap.span_to_snippet(span) {
409 println!("Couldn't make snippet for span {:?}->{:?}",
410 self.codemap.lookup_char_pos(span.lo),
411 self.codemap.lookup_char_pos(span.hi));
417 // Returns true if we should skip the following item.
418 pub fn visit_attrs(&mut self, attrs: &[ast::Attribute]) -> bool {
419 if utils::contains_skip(attrs) {
423 let outers: Vec<_> = attrs.iter()
424 .filter(|a| a.node.style == ast::AttrStyle::Outer)
427 if outers.is_empty() {
431 let first = &outers[0];
432 self.format_missing_with_indent(first.span.lo);
434 let rewrite = outers.rewrite(&self.get_context(),
435 self.config.max_width - self.block_indent.width(),
438 self.buffer.push_str(&rewrite);
439 let last = outers.last().unwrap();
440 self.last_pos = last.span.hi;
444 fn walk_mod_items(&mut self, m: &ast::Mod) {
445 for item in &m.items {
446 self.visit_item(&item);
450 fn format_mod(&mut self, m: &ast::Mod, vis: ast::Visibility, s: Span, ident: ast::Ident) {
451 // Decide whether this is an inline mod or an external mod.
452 let local_file_name = self.codemap.span_to_filename(s);
453 let is_internal = local_file_name == self.codemap.span_to_filename(m.inner);
455 self.buffer.push_str(utils::format_visibility(vis));
456 self.buffer.push_str("mod ");
457 self.buffer.push_str(&ident.to_string());
460 self.buffer.push_str(" {");
461 self.last_pos = ::utils::span_after(s, "{", self.codemap);
462 self.block_indent = self.block_indent.block_indent(self.config);
463 self.walk_mod_items(m);
464 self.format_missing_with_indent(m.inner.hi - BytePos(1));
466 self.last_pos = m.inner.hi;
468 self.buffer.push_str(";");
469 self.last_pos = s.hi;
473 pub fn format_separate_mod(&mut self, m: &ast::Mod) {
474 let filemap = self.codemap.lookup_char_pos(m.inner.lo).file;
475 self.last_pos = filemap.start_pos;
476 self.block_indent = Indent::empty();
477 self.walk_mod_items(m);
478 self.format_missing(filemap.end_pos);
481 fn format_import(&mut self, vis: ast::Visibility, vp: &ast::ViewPath, span: Span) {
482 let vis = utils::format_visibility(vis);
483 let mut offset = self.block_indent;
484 offset.alignment += vis.len() + "use ".len();
486 match vp.rewrite(&self.get_context(),
487 self.config.max_width - offset.width() - 1,
489 Some(ref s) if s.is_empty() => {
490 // Format up to last newline
491 let prev_span = codemap::mk_sp(self.last_pos, span.lo);
492 let span_end = match self.snippet(prev_span).rfind('\n') {
493 Some(offset) => self.last_pos + BytePos(offset as u32),
496 self.format_missing(span_end);
497 self.last_pos = span.hi;
500 let s = format!("{}use {};", vis, s);
501 self.format_missing_with_indent(span.lo);
502 self.buffer.push_str(&s);
503 self.last_pos = span.hi;
506 self.format_missing_with_indent(span.lo);
507 self.format_missing(span.hi);
512 pub fn get_context(&self) -> RewriteContext {
514 parse_session: self.parse_session,
515 codemap: self.codemap,
517 block_indent: self.block_indent,
522 impl<'a> Rewrite for [ast::Attribute] {
523 fn rewrite(&self, context: &RewriteContext, _: usize, offset: Indent) -> Option<String> {
524 let mut result = String::new();
528 let indent = offset.to_string(context.config);
530 for (i, a) in self.iter().enumerate() {
531 let a_str = context.snippet(a.span);
533 // Write comments and blank lines between attributes.
535 let comment = context.snippet(codemap::mk_sp(self[i - 1].span.hi, a.span.lo));
536 // This particular horror show is to preserve line breaks in between doc
537 // comments. An alternative would be to force such line breaks to start
538 // with the usual doc comment token.
539 let multi_line = a_str.starts_with("//") && comment.matches('\n').count() > 1;
540 let comment = comment.trim();
541 if !comment.is_empty() {
542 let comment = try_opt!(rewrite_comment(comment,
544 context.config.max_width -
548 result.push_str(&indent);
549 result.push_str(&comment);
551 } else if multi_line {
554 result.push_str(&indent);
557 // Write the attribute itself.
558 result.push_str(&a_str);
560 if i < self.len() - 1 {