1 //! Searching for matches.
5 resolving::{ResolvedPath, ResolvedPattern, ResolvedRule},
9 base_db::{FileId, FileRange},
11 search::{SearchScope, UsageSearchResult},
13 use rustc_hash::FxHashSet;
14 use syntax::{ast, AstNode, SyntaxKind, SyntaxNode};
16 /// A cache for the results of find_usages. This is for when we have multiple patterns that have the
17 /// same path. e.g. if the pattern was `foo::Bar` that can parse as a path, an expression, a type
18 /// and as a pattern. In each, the usages of `foo::Bar` are the same and we'd like to avoid finding
19 /// them more than once.
21 pub(crate) struct UsageCache {
22 usages: Vec<(Definition, UsageSearchResult)>,
25 impl<'db> MatchFinder<'db> {
26 /// Adds all matches for `rule` to `matches_out`. Matches may overlap in ways that make
27 /// replacement impossible, so further processing is required in order to properly nest matches
28 /// and remove overlapping matches. This is done in the `nesting` module.
29 pub(crate) fn find_matches_for_rule(
32 usage_cache: &mut UsageCache,
33 matches_out: &mut Vec<Match>,
35 if rule.pattern.contains_self {
36 // If the pattern contains `self` we restrict the scope of the search to just the
37 // current method. No other method can reference the same `self`. This makes the
38 // behavior of `self` consistent with other variables.
39 if let Some(current_function) = self.resolution_scope.current_function() {
40 self.slow_scan_node(¤t_function, rule, &None, matches_out);
44 if pick_path_for_usages(&rule.pattern).is_none() {
45 self.slow_scan(rule, matches_out);
48 self.find_matches_for_pattern_tree(rule, &rule.pattern, usage_cache, matches_out);
51 fn find_matches_for_pattern_tree(
54 pattern: &ResolvedPattern,
55 usage_cache: &mut UsageCache,
56 matches_out: &mut Vec<Match>,
58 if let Some(resolved_path) = pick_path_for_usages(pattern) {
59 let definition: Definition = resolved_path.resolution.clone().into();
60 for file_range in self.find_usages(usage_cache, definition).file_ranges() {
61 for node_to_match in self.find_nodes_to_match(resolved_path, file_range) {
62 if !is_search_permitted_ancestors(&node_to_match) {
63 cov_mark::hit!(use_declaration_with_braces);
66 self.try_add_match(rule, &node_to_match, &None, matches_out);
72 fn find_nodes_to_match(
74 resolved_path: &ResolvedPath,
75 file_range: FileRange,
76 ) -> Vec<SyntaxNode> {
77 let file = self.sema.parse(file_range.file_id);
78 let depth = resolved_path.depth as usize;
79 let offset = file_range.range.start();
83 .find_nodes_at_offset_with_descend::<ast::Path>(file.syntax(), offset)
86 if paths.peek().is_some() {
89 self.sema.ancestors_with_macros(path.syntax().clone()).nth(depth)
94 .find_nodes_at_offset_with_descend::<ast::MethodCallExpr>(file.syntax(), offset)
96 // If the pattern contained a path and we found a reference to that path that wasn't
97 // itself a path, but was a method call, then we need to adjust how far up to try
98 // matching by how deep the path was within a CallExpr. The structure would have been
99 // CallExpr, PathExpr, Path - i.e. a depth offset of 2. We don't need to check if the
100 // path was part of a CallExpr because if it wasn't then all that will happen is we'll
101 // fail to match, which is the desired behavior.
102 const PATH_DEPTH_IN_CALL_EXPR: usize = 2;
103 if depth < PATH_DEPTH_IN_CALL_EXPR {
107 .ancestors_with_macros(path.syntax().clone())
108 .nth(depth - PATH_DEPTH_IN_CALL_EXPR)
116 usage_cache: &'a mut UsageCache,
117 definition: Definition,
118 ) -> &'a UsageSearchResult {
119 // Logically if a lookup succeeds we should just return it. Unfortunately returning it would
120 // extend the lifetime of the borrow, then we wouldn't be able to do the insertion on a
121 // cache miss. This is a limitation of NLL and is fixed with Polonius. For now we do two
122 // lookups in the case of a cache hit.
123 if usage_cache.find(&definition).is_none() {
124 let usages = definition.usages(&self.sema).in_scope(self.search_scope()).all();
125 usage_cache.usages.push((definition, usages));
126 return &usage_cache.usages.last().unwrap().1;
128 usage_cache.find(&definition).unwrap()
131 /// Returns the scope within which we want to search. We don't want un unrestricted search
132 /// scope, since we don't want to find references in external dependencies.
133 fn search_scope(&self) -> SearchScope {
134 // FIXME: We should ideally have a test that checks that we edit local roots and not library
135 // roots. This probably would require some changes to fixtures, since currently everything
136 // seems to get put into a single source root.
137 let mut files = Vec::new();
138 self.search_files_do(|file_id| {
141 SearchScope::files(&files)
144 fn slow_scan(&self, rule: &ResolvedRule, matches_out: &mut Vec<Match>) {
145 self.search_files_do(|file_id| {
146 let file = self.sema.parse(file_id);
147 let code = file.syntax();
148 self.slow_scan_node(code, rule, &None, matches_out);
152 fn search_files_do(&self, mut callback: impl FnMut(FileId)) {
153 if self.restrict_ranges.is_empty() {
154 // Unrestricted search.
155 use ide_db::base_db::SourceDatabaseExt;
156 use ide_db::symbol_index::SymbolsDatabase;
157 for &root in self.sema.db.local_roots().iter() {
158 let sr = self.sema.db.source_root(root);
159 for file_id in sr.iter() {
164 // Search is restricted, deduplicate file IDs (generally only one).
165 let mut files = FxHashSet::default();
166 for range in &self.restrict_ranges {
167 if files.insert(range.file_id) {
168 callback(range.file_id);
178 restrict_range: &Option<FileRange>,
179 matches_out: &mut Vec<Match>,
181 if !is_search_permitted(code) {
184 self.try_add_match(rule, code, restrict_range, matches_out);
185 // If we've got a macro call, we already tried matching it pre-expansion, which is the only
186 // way to match the whole macro, now try expanding it and matching the expansion.
187 if let Some(macro_call) = ast::MacroCall::cast(code.clone()) {
188 if let Some(expanded) = self.sema.expand(¯o_call) {
189 if let Some(tt) = macro_call.token_tree() {
190 // When matching within a macro expansion, we only want to allow matches of
191 // nodes that originated entirely from within the token tree of the macro call.
192 // i.e. we don't want to match something that came from the macro itself.
196 &Some(self.sema.original_range(tt.syntax())),
202 for child in code.children() {
203 self.slow_scan_node(&child, rule, restrict_range, matches_out);
211 restrict_range: &Option<FileRange>,
212 matches_out: &mut Vec<Match>,
214 if !self.within_range_restrictions(code) {
215 cov_mark::hit!(replace_nonpath_within_selection);
218 if let Ok(m) = matching::get_match(false, rule, code, restrict_range, &self.sema) {
223 /// Returns whether `code` is within one of our range restrictions if we have any. No range
224 /// restrictions is considered unrestricted and always returns true.
225 fn within_range_restrictions(&self, code: &SyntaxNode) -> bool {
226 if self.restrict_ranges.is_empty() {
227 // There is no range restriction.
230 let node_range = self.sema.original_range(code);
231 for range in &self.restrict_ranges {
232 if range.file_id == node_range.file_id && range.range.contains_range(node_range.range) {
240 /// Returns whether we support matching within `node` and all of its ancestors.
241 fn is_search_permitted_ancestors(node: &SyntaxNode) -> bool {
242 if let Some(parent) = node.parent() {
243 if !is_search_permitted_ancestors(&parent) {
247 is_search_permitted(node)
250 /// Returns whether we support matching within this kind of node.
251 fn is_search_permitted(node: &SyntaxNode) -> bool {
252 // FIXME: Properly handle use declarations. At the moment, if our search pattern is `foo::bar`
253 // and the code is `use foo::{baz, bar}`, we'll match `bar`, since it resolves to `foo::bar`.
254 // However we'll then replace just the part we matched `bar`. We probably need to instead remove
255 // `bar` and insert a new use declaration.
256 node.kind() != SyntaxKind::USE
260 fn find(&mut self, definition: &Definition) -> Option<&UsageSearchResult> {
261 // We expect a very small number of cache entries (generally 1), so a linear scan should be
262 // fast enough and avoids the need to implement Hash for Definition.
263 for (d, refs) in &self.usages {
272 /// Returns a path that's suitable for path resolution. We exclude builtin types, since they aren't
273 /// something that we can find references to. We then somewhat arbitrarily pick the path that is the
274 /// longest as this is hopefully more likely to be less common, making it faster to find.
275 fn pick_path_for_usages(pattern: &ResolvedPattern) -> Option<&ResolvedPath> {
276 // FIXME: Take the scope of the resolved path into account. e.g. if there are any paths that are
277 // private to the current module, then we definitely would want to pick them over say a path
278 // from std. Possibly we should go further than this and intersect the search scopes for all
279 // resolved paths then search only in that scope.
284 !matches!(p.resolution, hir::PathResolution::Def(hir::ModuleDef::BuiltinType(_)))
286 .map(|(node, resolved)| (node.text().len(), resolved))
287 .max_by(|(a, _), (b, _)| a.cmp(b))
288 .map(|(_, resolved)| resolved)