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| 1 | +use crate::utils::span_lint_and_sugg; |
| 2 | +use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass}; |
| 3 | +use rustc::{declare_lint_pass, declare_tool_lint}; |
| 4 | +use rustc_errors::Applicability; |
| 5 | +use std::convert::TryFrom; |
| 6 | +use syntax::ast; |
| 7 | +use syntax::source_map::{BytePos, Span}; |
| 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 | + let new_span = Span::new( |
| 68 | + attr.span.lo() + BytePos(lo), |
| 69 | + attr.span.lo() + BytePos(hi), |
| 70 | + attr.span.ctxt(), |
| 71 | + ); |
| 72 | + span_lint_and_sugg( |
| 73 | + cx, |
| 74 | + TABS_IN_DOC_COMMENTS, |
| 75 | + new_span, |
| 76 | + "using tabs in doc comments is not recommended", |
| 77 | + "consider using four spaces per tab", |
| 78 | + " ".repeat((hi - lo) as usize), |
| 79 | + Applicability::MaybeIncorrect, |
| 80 | + ); |
| 81 | + } |
| 82 | + } |
| 83 | + } |
| 84 | +} |
| 85 | + |
| 86 | +impl EarlyLintPass for TabsInDocComments { |
| 87 | + fn check_attribute(&mut self, cx: &EarlyContext<'_>, attribute: &ast::Attribute) { |
| 88 | + Self::warn_if_tabs_in_doc(cx, &attribute); |
| 89 | + } |
| 90 | +} |
| 91 | + |
| 92 | +/// |
| 93 | +/// scans the string for groups of tabs and returns the start(inclusive) and end positions |
| 94 | +/// (exclusive) of all groups |
| 95 | +/// e.g. "sd\tasd\t\taa" will be converted to [(2, 3), (6, 8)] as |
| 96 | +/// 012 3456 7 89 |
| 97 | +/// ^-^ ^---^ |
| 98 | +fn get_chunks_of_tabs(the_str: &str) -> Vec<(u32, u32)> { |
| 99 | + let line_length_way_to_long = "doc comment longer than 2^32 chars"; |
| 100 | + let mut spans: Vec<(u32, u32)> = vec![]; |
| 101 | + let mut current_start: u32 = 0; |
| 102 | + |
| 103 | + // tracker to decide if the last group of tabs is not closed by a non-tab character |
| 104 | + let mut is_active = false; |
| 105 | + |
| 106 | + let chars_array: Vec<_> = the_str.chars().collect(); |
| 107 | + |
| 108 | + if chars_array == vec!['\t'] { |
| 109 | + return vec![(0, 1)]; |
| 110 | + } |
| 111 | + |
| 112 | + for (index, arr) in chars_array.windows(2).enumerate() { |
| 113 | + let index = u32::try_from(index).expect(line_length_way_to_long); |
| 114 | + match arr { |
| 115 | + ['\t', '\t'] => { |
| 116 | + // either string starts with double tab, then we have to set it active, |
| 117 | + // otherwise is_active is true anyway |
| 118 | + is_active = true; |
| 119 | + }, |
| 120 | + [_, '\t'] => { |
| 121 | + // as ['\t', '\t'] is excluded, this has to be a start of a tab group, |
| 122 | + // set indices accordingly |
| 123 | + is_active = true; |
| 124 | + current_start = index + 1; |
| 125 | + }, |
| 126 | + ['\t', _] => { |
| 127 | + // this now has to be an end of the group, hence we have to push a new tuple |
| 128 | + is_active = false; |
| 129 | + spans.push((current_start, index + 1)); |
| 130 | + }, |
| 131 | + _ => {}, |
| 132 | + } |
| 133 | + } |
| 134 | + |
| 135 | + // only possible when tabs are at the end, insert last group |
| 136 | + if is_active { |
| 137 | + spans.push(( |
| 138 | + current_start, |
| 139 | + u32::try_from(the_str.chars().count()).expect(line_length_way_to_long), |
| 140 | + )); |
| 141 | + } |
| 142 | + |
| 143 | + spans |
| 144 | +} |
| 145 | + |
| 146 | +#[cfg(test)] |
| 147 | +mod tests_for_get_chunks_of_tabs { |
| 148 | + use super::get_chunks_of_tabs; |
| 149 | + |
| 150 | + #[test] |
| 151 | + fn test_empty_string() { |
| 152 | + let res = get_chunks_of_tabs(""); |
| 153 | + |
| 154 | + assert_eq!(res, vec![]); |
| 155 | + } |
| 156 | + |
| 157 | + #[test] |
| 158 | + fn test_simple() { |
| 159 | + let res = get_chunks_of_tabs("sd\t\t\taa"); |
| 160 | + |
| 161 | + assert_eq!(res, vec![(2, 5)]); |
| 162 | + } |
| 163 | + |
| 164 | + #[test] |
| 165 | + fn test_only_t() { |
| 166 | + let res = get_chunks_of_tabs("\t\t"); |
| 167 | + |
| 168 | + assert_eq!(res, vec![(0, 2)]); |
| 169 | + } |
| 170 | + |
| 171 | + #[test] |
| 172 | + fn test_only_one_t() { |
| 173 | + let res = get_chunks_of_tabs("\t"); |
| 174 | + |
| 175 | + assert_eq!(res, vec![(0, 1)]); |
| 176 | + } |
| 177 | + |
| 178 | + #[test] |
| 179 | + fn test_double() { |
| 180 | + let res = get_chunks_of_tabs("sd\tasd\t\taa"); |
| 181 | + |
| 182 | + assert_eq!(res, vec![(2, 3), (6, 8)]); |
| 183 | + } |
| 184 | + |
| 185 | + #[test] |
| 186 | + fn test_start() { |
| 187 | + let res = get_chunks_of_tabs("\t\taa"); |
| 188 | + |
| 189 | + assert_eq!(res, vec![(0, 2)]); |
| 190 | + } |
| 191 | + |
| 192 | + #[test] |
| 193 | + fn test_end() { |
| 194 | + let res = get_chunks_of_tabs("aa\t\t"); |
| 195 | + |
| 196 | + assert_eq!(res, vec![(2, 4)]); |
| 197 | + } |
| 198 | + |
| 199 | + #[test] |
| 200 | + fn test_start_single() { |
| 201 | + let res = get_chunks_of_tabs("\taa"); |
| 202 | + |
| 203 | + assert_eq!(res, vec![(0, 1)]); |
| 204 | + } |
| 205 | + |
| 206 | + #[test] |
| 207 | + fn test_end_single() { |
| 208 | + let res = get_chunks_of_tabs("aa\t"); |
| 209 | + |
| 210 | + assert_eq!(res, vec![(2, 3)]); |
| 211 | + } |
| 212 | + |
| 213 | + #[test] |
| 214 | + fn test_no_tabs() { |
| 215 | + let res = get_chunks_of_tabs("dsfs"); |
| 216 | + |
| 217 | + assert_eq!(res, vec![]); |
| 218 | + } |
| 219 | +} |
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