]>
Commit | Line | Data |
---|---|---|
f20569fa XL |
1 | use crate::utils::span_lint_and_sugg; |
2 | use rustc_ast::ast; | |
3 | use rustc_errors::Applicability; | |
4 | use rustc_lint::{EarlyContext, EarlyLintPass}; | |
5 | use rustc_session::{declare_lint_pass, declare_tool_lint}; | |
6 | use rustc_span::source_map::{BytePos, Span}; | |
7 | use std::convert::TryFrom; | |
8 | ||
9 | declare_clippy_lint! { | |
10 | /// **What it does:** Checks doc comments for usage of tab characters. | |
11 | /// | |
12 | /// **Why is this bad?** The rust style-guide promotes spaces instead of tabs for indentation. | |
13 | /// To keep a consistent view on the source, also doc comments should not have tabs. | |
14 | /// Also, explaining ascii-diagrams containing tabs can get displayed incorrectly when the | |
15 | /// display settings of the author and reader differ. | |
16 | /// | |
17 | /// **Known problems:** None. | |
18 | /// | |
19 | /// **Example:** | |
20 | /// ```rust | |
21 | /// /// | |
22 | /// /// Struct to hold two strings: | |
23 | /// /// - first one | |
24 | /// /// - second one | |
25 | /// pub struct DoubleString { | |
26 | /// /// | |
27 | /// /// - First String: | |
28 | /// /// - needs to be inside here | |
29 | /// first_string: String, | |
30 | /// /// | |
31 | /// /// - Second String: | |
32 | /// /// - needs to be inside here | |
33 | /// second_string: String, | |
34 | ///} | |
35 | /// ``` | |
36 | /// | |
37 | /// Will be converted to: | |
38 | /// ```rust | |
39 | /// /// | |
40 | /// /// Struct to hold two strings: | |
41 | /// /// - first one | |
42 | /// /// - second one | |
43 | /// pub struct DoubleString { | |
44 | /// /// | |
45 | /// /// - First String: | |
46 | /// /// - needs to be inside here | |
47 | /// first_string: String, | |
48 | /// /// | |
49 | /// /// - Second String: | |
50 | /// /// - needs to be inside here | |
51 | /// second_string: String, | |
52 | ///} | |
53 | /// ``` | |
54 | pub TABS_IN_DOC_COMMENTS, | |
55 | style, | |
56 | "using tabs in doc comments is not recommended" | |
57 | } | |
58 | ||
59 | declare_lint_pass!(TabsInDocComments => [TABS_IN_DOC_COMMENTS]); | |
60 | ||
61 | impl TabsInDocComments { | |
62 | fn warn_if_tabs_in_doc(cx: &EarlyContext<'_>, attr: &ast::Attribute) { | |
63 | if let ast::AttrKind::DocComment(_, comment) = attr.kind { | |
64 | let comment = comment.as_str(); | |
65 | ||
66 | for (lo, hi) in get_chunks_of_tabs(&comment) { | |
67 | // +3 skips the opening delimiter | |
68 | let new_span = Span::new( | |
69 | attr.span.lo() + BytePos(3 + lo), | |
70 | attr.span.lo() + BytePos(3 + hi), | |
71 | attr.span.ctxt(), | |
72 | ); | |
73 | span_lint_and_sugg( | |
74 | cx, | |
75 | TABS_IN_DOC_COMMENTS, | |
76 | new_span, | |
77 | "using tabs in doc comments is not recommended", | |
78 | "consider using four spaces per tab", | |
79 | " ".repeat((hi - lo) as usize), | |
80 | Applicability::MaybeIncorrect, | |
81 | ); | |
82 | } | |
83 | } | |
84 | } | |
85 | } | |
86 | ||
87 | impl EarlyLintPass for TabsInDocComments { | |
88 | fn check_attribute(&mut self, cx: &EarlyContext<'_>, attribute: &ast::Attribute) { | |
89 | Self::warn_if_tabs_in_doc(cx, &attribute); | |
90 | } | |
91 | } | |
92 | ||
93 | /// | |
94 | /// scans the string for groups of tabs and returns the start(inclusive) and end positions | |
95 | /// (exclusive) of all groups | |
96 | /// e.g. "sd\tasd\t\taa" will be converted to [(2, 3), (6, 8)] as | |
97 | /// 012 3456 7 89 | |
98 | /// ^-^ ^---^ | |
99 | fn get_chunks_of_tabs(the_str: &str) -> Vec<(u32, u32)> { | |
100 | let line_length_way_to_long = "doc comment longer than 2^32 chars"; | |
101 | let mut spans: Vec<(u32, u32)> = vec![]; | |
102 | let mut current_start: u32 = 0; | |
103 | ||
104 | // tracker to decide if the last group of tabs is not closed by a non-tab character | |
105 | let mut is_active = false; | |
106 | ||
107 | let chars_array: Vec<_> = the_str.chars().collect(); | |
108 | ||
109 | if chars_array == vec!['\t'] { | |
110 | return vec![(0, 1)]; | |
111 | } | |
112 | ||
113 | for (index, arr) in chars_array.windows(2).enumerate() { | |
114 | let index = u32::try_from(index).expect(line_length_way_to_long); | |
115 | match arr { | |
116 | ['\t', '\t'] => { | |
117 | // either string starts with double tab, then we have to set it active, | |
118 | // otherwise is_active is true anyway | |
119 | is_active = true; | |
120 | }, | |
121 | [_, '\t'] => { | |
122 | // as ['\t', '\t'] is excluded, this has to be a start of a tab group, | |
123 | // set indices accordingly | |
124 | is_active = true; | |
125 | current_start = index + 1; | |
126 | }, | |
127 | ['\t', _] => { | |
128 | // this now has to be an end of the group, hence we have to push a new tuple | |
129 | is_active = false; | |
130 | spans.push((current_start, index + 1)); | |
131 | }, | |
132 | _ => {}, | |
133 | } | |
134 | } | |
135 | ||
136 | // only possible when tabs are at the end, insert last group | |
137 | if is_active { | |
138 | spans.push(( | |
139 | current_start, | |
140 | u32::try_from(the_str.chars().count()).expect(line_length_way_to_long), | |
141 | )); | |
142 | } | |
143 | ||
144 | spans | |
145 | } | |
146 | ||
147 | #[cfg(test)] | |
148 | mod tests_for_get_chunks_of_tabs { | |
149 | use super::get_chunks_of_tabs; | |
150 | ||
151 | #[test] | |
152 | fn test_empty_string() { | |
153 | let res = get_chunks_of_tabs(""); | |
154 | ||
155 | assert_eq!(res, vec![]); | |
156 | } | |
157 | ||
158 | #[test] | |
159 | fn test_simple() { | |
160 | let res = get_chunks_of_tabs("sd\t\t\taa"); | |
161 | ||
162 | assert_eq!(res, vec![(2, 5)]); | |
163 | } | |
164 | ||
165 | #[test] | |
166 | fn test_only_t() { | |
167 | let res = get_chunks_of_tabs("\t\t"); | |
168 | ||
169 | assert_eq!(res, vec![(0, 2)]); | |
170 | } | |
171 | ||
172 | #[test] | |
173 | fn test_only_one_t() { | |
174 | let res = get_chunks_of_tabs("\t"); | |
175 | ||
176 | assert_eq!(res, vec![(0, 1)]); | |
177 | } | |
178 | ||
179 | #[test] | |
180 | fn test_double() { | |
181 | let res = get_chunks_of_tabs("sd\tasd\t\taa"); | |
182 | ||
183 | assert_eq!(res, vec![(2, 3), (6, 8)]); | |
184 | } | |
185 | ||
186 | #[test] | |
187 | fn test_start() { | |
188 | let res = get_chunks_of_tabs("\t\taa"); | |
189 | ||
190 | assert_eq!(res, vec![(0, 2)]); | |
191 | } | |
192 | ||
193 | #[test] | |
194 | fn test_end() { | |
195 | let res = get_chunks_of_tabs("aa\t\t"); | |
196 | ||
197 | assert_eq!(res, vec![(2, 4)]); | |
198 | } | |
199 | ||
200 | #[test] | |
201 | fn test_start_single() { | |
202 | let res = get_chunks_of_tabs("\taa"); | |
203 | ||
204 | assert_eq!(res, vec![(0, 1)]); | |
205 | } | |
206 | ||
207 | #[test] | |
208 | fn test_end_single() { | |
209 | let res = get_chunks_of_tabs("aa\t"); | |
210 | ||
211 | assert_eq!(res, vec![(2, 3)]); | |
212 | } | |
213 | ||
214 | #[test] | |
215 | fn test_no_tabs() { | |
216 | let res = get_chunks_of_tabs("dsfs"); | |
217 | ||
218 | assert_eq!(res, vec![]); | |
219 | } | |
220 | } |