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 config::WriteMode;
12 use visitor::FmtVisitor;
13 use syntax::codemap::{self, BytePos, Span, Pos};
14 use comment::{CodeCharKind, CommentCodeSlices, rewrite_comment};
16 impl<'a> FmtVisitor<'a> {
17 fn output_at_start(&self) -> bool {
21 // TODO these format_missing methods are ugly. Refactor and add unit tests
22 // for the central whitespace stripping loop.
23 pub fn format_missing(&mut self, end: BytePos) {
24 self.format_missing_inner(end,
25 |this, last_snippet, _| this.buffer.push_str(last_snippet))
28 pub fn format_missing_with_indent(&mut self, end: BytePos) {
29 let config = self.config;
30 self.format_missing_inner(end, |this, last_snippet, snippet| {
31 this.buffer.push_str(last_snippet.trim_right());
32 if last_snippet == snippet && !this.output_at_start() {
33 // No new lines in the snippet.
34 this.buffer.push_str("\n");
36 let indent = this.block_indent.to_string(config);
37 this.buffer.push_str(&indent);
41 pub fn format_missing_no_indent(&mut self, end: BytePos) {
42 self.format_missing_inner(end, |this, last_snippet, _| {
43 this.buffer.push_str(last_snippet.trim_right());
47 fn format_missing_inner<F: Fn(&mut FmtVisitor, &str, &str)>(&mut self,
49 process_last_snippet: F) {
50 let start = self.last_pos;
53 // Do nothing if this is the beginning of the file.
54 if !self.output_at_start() {
55 process_last_snippet(self, "", "");
61 "Request to format inverted span: {:?} to {:?}",
62 self.codemap.lookup_char_pos(start),
63 self.codemap.lookup_char_pos(end));
66 let span = codemap::mk_sp(start, end);
68 self.write_snippet(span, &process_last_snippet);
71 fn write_snippet<F>(&mut self, span: Span, process_last_snippet: F)
72 where F: Fn(&mut FmtVisitor, &str, &str)
74 // Get a snippet from the file start to the span's hi without allocating.
75 // We need it to determine what precedes the current comment. If the comment
76 // follows code on the same line, we won't touch it.
77 let big_span_lo = self.codemap.lookup_char_pos(span.lo).file.start_pos;
78 let local_begin = self.codemap.lookup_byte_offset(big_span_lo);
79 let local_end = self.codemap.lookup_byte_offset(span.hi);
80 let start_index = local_begin.pos.to_usize();
81 let end_index = local_end.pos.to_usize();
82 let big_snippet = &local_begin.fm.src.as_ref().unwrap()[start_index..end_index];
84 let big_diff = (span.lo - big_span_lo).to_usize();
85 let snippet = self.snippet(span);
87 self.write_snippet_inner(big_snippet, big_diff, &snippet, process_last_snippet);
90 fn write_snippet_inner<F>(&mut self,
94 process_last_snippet: F)
95 where F: Fn(&mut FmtVisitor, &str, &str)
97 // Trim whitespace from the right hand side of each line.
98 // Annoyingly, the library functions for splitting by lines etc. are not
99 // quite right, so we must do it ourselves.
100 let mut line_start = 0;
101 let mut last_wspace = None;
102 let mut rewrite_next_comment = true;
104 fn replace_chars(string: &str) -> String {
106 .map(|ch| { if ch.is_whitespace() { ch } else { 'X' } })
110 let replaced = match self.config.write_mode {
111 WriteMode::Coverage => replace_chars(old_snippet),
112 _ => old_snippet.to_owned(),
114 let snippet = &*replaced;
116 for (kind, offset, subslice) in CommentCodeSlices::new(snippet) {
117 if let CodeCharKind::Comment = kind {
118 let last_char = big_snippet[..(offset + big_diff)]
121 .skip_while(|rev_c| [' ', '\t'].contains(rev_c))
124 let fix_indent = last_char.map_or(true, |rev_c| ['{', '\n'].contains(&rev_c));
126 if rewrite_next_comment && fix_indent {
127 if let Some('{') = last_char {
128 self.buffer.push_str("\n");
131 let comment_width = ::std::cmp::min(self.config.ideal_width,
132 self.config.max_width -
133 self.block_indent.width());
135 self.buffer.push_str(&self.block_indent.to_string(self.config));
136 self.buffer.push_str(&rewrite_comment(subslice,
144 line_start = offset + subslice.len();
146 if let Some('/') = subslice.chars().skip(1).next() {
147 // Add a newline after line comments
148 self.buffer.push_str("\n");
149 } else if line_start <= snippet.len() {
150 // For other comments add a newline if there isn't one at the end already
151 match snippet[line_start..].chars().next() {
152 Some('\n') | Some('\r') => (),
153 _ => self.buffer.push_str("\n"),
159 rewrite_next_comment = false;
163 for (mut i, c) in subslice.char_indices() {
167 if let Some(lw) = last_wspace {
168 self.buffer.push_str(&snippet[line_start..lw]);
169 self.buffer.push_str("\n");
171 self.buffer.push_str(&snippet[line_start..i + 1]);
176 rewrite_next_comment = rewrite_next_comment || kind == CodeCharKind::Normal;
177 } else if c.is_whitespace() {
178 if last_wspace.is_none() {
179 last_wspace = Some(i);
182 if last_wspace.is_some() {
186 rewrite_next_comment = rewrite_next_comment || kind == CodeCharKind::Normal;
189 rewrite_next_comment = rewrite_next_comment || kind == CodeCharKind::Normal;
195 process_last_snippet(self, &snippet[line_start..], snippet);