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| 1 | +use std::ops::Range; |
| 2 | + |
| 3 | +use pulldown_cmark::{Parser, BrokenLink, Event, Tag, LinkType, OffsetIter}; |
| 4 | +use rustc_ast::NodeId; |
| 5 | +use rustc_errors::SuggestionStyle; |
| 6 | +use rustc_hir::HirId; |
| 7 | +use rustc_hir::def::{Namespace, DefKind, DocLinkResMap, Res}; |
| 8 | +use rustc_lint_defs::Applicability; |
| 9 | +use rustc_span::Symbol; |
| 10 | + |
| 11 | +use crate::clean::Item; |
| 12 | +use crate::clean::utils::find_nearest_parent_module; |
| 13 | +use crate::core::DocContext; |
| 14 | +use crate::html::markdown::main_body_opts; |
| 15 | +use crate::passes::source_span_for_markdown_range; |
| 16 | + |
| 17 | +struct LinkData { |
| 18 | + resolvable_link: Option<String>, |
| 19 | + resolvable_link_range: Option<Range<usize>>, |
| 20 | + display_link: String, |
| 21 | +} |
| 22 | + |
| 23 | +pub(crate) fn visit_item(cx: &DocContext<'_>, item: &Item) { |
| 24 | + let Some(hir_id) = DocContext::as_local_hir_id(cx.tcx, item.item_id) else { |
| 25 | + // If non-local, no need to check anything. |
| 26 | + return; |
| 27 | + }; |
| 28 | + |
| 29 | + let doc = item.doc_value(); |
| 30 | + if doc.is_empty() { |
| 31 | + return; |
| 32 | + } |
| 33 | + |
| 34 | + check_redundant_explicit_link(cx, item, hir_id, &doc); |
| 35 | +} |
| 36 | + |
| 37 | +fn check_redundant_explicit_link<'md>(cx: &DocContext<'_>, item: &Item, hir_id: HirId, doc: &'md str) { |
| 38 | + let mut broken_line_callback = |link: BrokenLink<'md>| Some((link.reference, "".into())); |
| 39 | + let mut offset_iter = Parser::new_with_broken_link_callback(&doc, main_body_opts(), Some(&mut broken_line_callback)).into_offset_iter(); |
| 40 | + |
| 41 | + while let Some((event, link_range)) = offset_iter.next() { |
| 42 | + match event { |
| 43 | + Event::Start(Tag::Link(link_type, dest, _)) => { |
| 44 | + let link_data = collect_link_data(&mut offset_iter); |
| 45 | + let dest = dest.to_string(); |
| 46 | + |
| 47 | + if link_type == LinkType::Inline { |
| 48 | + check_inline_link_redundancy(cx, item, hir_id, doc, link_range, dest, link_data); |
| 49 | + } |
| 50 | + } |
| 51 | + _ => {} |
| 52 | + } |
| 53 | + } |
| 54 | +} |
| 55 | + |
| 56 | +fn check_inline_link_redundancy(cx: &DocContext<'_>, item: &Item, hir_id: HirId, doc: &str, link_range: Range<usize>, dest: String, link_data: LinkData) -> Option<()> { |
| 57 | + let item_id = item.def_id()?; |
| 58 | + let module_id = match cx.tcx.def_kind(item_id) { |
| 59 | + DefKind::Mod if item.inner_docs(cx.tcx) => item_id, |
| 60 | + _ => find_nearest_parent_module(cx.tcx, item_id).unwrap(), |
| 61 | + }; |
| 62 | + let resolutions = cx.tcx.doc_link_resolutions(module_id); |
| 63 | + |
| 64 | + let (resolvable_link, resolvable_link_range) = (&link_data.resolvable_link?, &link_data.resolvable_link_range?); |
| 65 | + let (dest_res, display_res) = (find_resolution(resolutions, &dest)?, find_resolution(resolutions, resolvable_link)?); |
| 66 | + |
| 67 | + if dest_res == display_res { |
| 68 | + let link_span = source_span_for_markdown_range( |
| 69 | + cx.tcx, |
| 70 | + &doc, |
| 71 | + &link_range, |
| 72 | + &item.attrs, |
| 73 | + ).unwrap_or(item.attr_span(cx.tcx)); |
| 74 | + let explicit_span = source_span_for_markdown_range( |
| 75 | + cx.tcx, |
| 76 | + &doc, |
| 77 | + &offset_explicit_range(doc, &link_range, b'(', b')'), |
| 78 | + &item.attrs |
| 79 | + )?; |
| 80 | + let display_span = source_span_for_markdown_range( |
| 81 | + cx.tcx, |
| 82 | + &doc, |
| 83 | + &resolvable_link_range, |
| 84 | + &item.attrs |
| 85 | + )?; |
| 86 | + |
| 87 | + |
| 88 | + cx.tcx.struct_span_lint_hir(crate::lint::REDUNDANT_EXPLICIT_LINKS, hir_id, explicit_span, "redundant explicit link target", |lint| { |
| 89 | + lint.span_label(explicit_span, "explicit target is redundant") |
| 90 | + .span_label(display_span, "because label contains path that resolves to same destination") |
| 91 | + .note("when a link's destination is not specified,\nthe label is used to resolve intra-doc links") |
| 92 | + .span_suggestion_with_style(link_span, "remove explicit link target", format!("[{}]", link_data.display_link), Applicability::MaybeIncorrect, SuggestionStyle::ShowAlways); |
| 93 | + |
| 94 | + lint |
| 95 | + }); |
| 96 | + } |
| 97 | + |
| 98 | + None |
| 99 | +} |
| 100 | + |
| 101 | +fn find_resolution<'tcx>(resolutions: &'tcx DocLinkResMap, path: &str) -> Option<&'tcx Res<NodeId>> { |
| 102 | + for ns in [Namespace::TypeNS, Namespace::ValueNS, Namespace::MacroNS] { |
| 103 | + let Some(Some(res)) = resolutions.get(&(Symbol::intern(path), ns)) |
| 104 | + else { |
| 105 | + continue; |
| 106 | + }; |
| 107 | + |
| 108 | + return Some(res); |
| 109 | + } |
| 110 | + |
| 111 | + None |
| 112 | +} |
| 113 | + |
| 114 | +/// Collects all neccessary data of link. |
| 115 | +fn collect_link_data(offset_iter: &mut OffsetIter<'_, '_>) -> LinkData { |
| 116 | + let mut resolvable_link = None; |
| 117 | + let mut resolvable_link_range = None; |
| 118 | + let mut display_link = String::new(); |
| 119 | + |
| 120 | + while let Some((event, range)) = offset_iter.next() { |
| 121 | + match event { |
| 122 | + Event::Text(code) => { |
| 123 | + let code = code.to_string(); |
| 124 | + display_link.push_str(&code); |
| 125 | + resolvable_link = Some(code); |
| 126 | + resolvable_link_range = Some(range); |
| 127 | + } |
| 128 | + Event::Code(code) => { |
| 129 | + let code = code.to_string(); |
| 130 | + display_link.push('`'); |
| 131 | + display_link.push_str(&code); |
| 132 | + display_link.push('`'); |
| 133 | + resolvable_link = Some(code); |
| 134 | + resolvable_link_range = Some(range); |
| 135 | + } |
| 136 | + Event::End(_) => { |
| 137 | + break; |
| 138 | + } |
| 139 | + _ => {} |
| 140 | + } |
| 141 | + } |
| 142 | + |
| 143 | + LinkData { |
| 144 | + resolvable_link, |
| 145 | + resolvable_link_range, |
| 146 | + display_link, |
| 147 | + } |
| 148 | +} |
| 149 | + |
| 150 | +fn offset_explicit_range(md: &str, link_range: &Range<usize>, open: u8, close: u8) -> Range<usize> { |
| 151 | + let mut open_brace = !0; |
| 152 | + let mut close_brace = !0; |
| 153 | + for (i, b) in md.as_bytes()[link_range.clone()].iter().copied().enumerate().rev() { |
| 154 | + let i = i + link_range.start; |
| 155 | + if b == close { |
| 156 | + close_brace = i; |
| 157 | + break; |
| 158 | + } |
| 159 | + } |
| 160 | + |
| 161 | + if close_brace < link_range.start || close_brace >= link_range.end { |
| 162 | + return link_range.clone(); |
| 163 | + } |
| 164 | + |
| 165 | + let mut nesting = 1; |
| 166 | + |
| 167 | + for (i, b) in md.as_bytes()[link_range.start..close_brace].iter().copied().enumerate().rev() { |
| 168 | + let i = i + link_range.start; |
| 169 | + if b == close { |
| 170 | + nesting += 1; |
| 171 | + } |
| 172 | + if b == open { |
| 173 | + nesting -= 1; |
| 174 | + } |
| 175 | + if nesting == 0 { |
| 176 | + open_brace = i; |
| 177 | + break; |
| 178 | + } |
| 179 | + } |
| 180 | + |
| 181 | + assert!(open_brace != close_brace); |
| 182 | + |
| 183 | + if open_brace < link_range.start || open_brace >= link_range.end { |
| 184 | + return link_range.clone(); |
| 185 | + } |
| 186 | + // do not actually include braces in the span |
| 187 | + (open_brace + 1)..close_brace |
| 188 | +} |
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