Less allocs

Author: Veykril

src/tools/rust-analyzer/crates/ide-db/src/imports/import_assets.rs

@@ -1,5 +1,7 @@
 //! Look up accessible paths for items.
 
+use std::ops::ControlFlow;
+
 use hir::{
     db::HirDatabase, AsAssocItem, AssocItem, AssocItemContainer, Crate, HasCrate, ImportPathConfig,
     ItemInNs, ModPath, Module, ModuleDef, PathResolution, PrefixKind, ScopeDef, Semantics,
@@ -353,6 +355,7 @@ fn path_applicable_imports(
         // we have some unresolved qualifier that we search an import for
         // The key here is that whatever we import must form a resolved path for the remainder of
         // what follows
+        // FIXME: This doesn't handle visibility
         [first_qsegment, qualifier_rest @ ..] => items_locator::items_with_name(
             sema,
             current_crate,
@@ -417,8 +420,11 @@ fn validate_resolvable(
                 module,
                 candidate.clone(),
                 AssocSearchMode::Exclude,
+                |it| match scope_filter(it) {
+                    true => ControlFlow::Break(it),
+                    false => ControlFlow::Continue(()),
+                },
             )
-            .find(|&it| scope_filter(it))
             .map(|item| LocatedImport::new(import_path_candidate, resolved_qualifier, item))
         }
         // FIXME

src/tools/rust-analyzer/crates/ide-db/src/items_locator.rs

@@ -2,6 +2,8 @@
 //! by its name and a few criteria.
 //! The main reason for this module to exist is the fact that project's items and dependencies' items
 //! are located in different caches, with different APIs.
+use std::ops::ControlFlow;
+
 use either::Either;
 use hir::{import_map, Crate, ItemInNs, Module, Semantics};
 use limit::Limit;
@@ -17,6 +19,7 @@ pub static DEFAULT_QUERY_SEARCH_LIMIT: Limit = Limit::new(100);
 
 pub use import_map::AssocSearchMode;
 
+// FIXME: Do callbacks instead to avoid allocations.
 /// Searches for importable items with the given name in the crate and its dependencies.
 pub fn items_with_name<'a>(
     sema: &'a Semantics<'_, RootDatabase>,
@@ -70,12 +73,13 @@ pub fn items_with_name<'a>(
 }
 
 /// Searches for importable items with the given name in the crate and its dependencies.
-pub fn items_with_name_in_module<'a>(
-    sema: &'a Semantics<'_, RootDatabase>,
+pub fn items_with_name_in_module<T>(
+    sema: &Semantics<'_, RootDatabase>,
     module: Module,
     name: NameToImport,
     assoc_item_search: AssocSearchMode,
-) -> impl Iterator<Item = ItemInNs> + 'a {
+    mut cb: impl FnMut(ItemInNs) -> ControlFlow<T>,
+) -> Option<T> {
     let _p = tracing::info_span!("items_with_name_in", name = name.text(), assoc_item_search = ?assoc_item_search, ?module)
         .entered();
 
@@ -107,15 +111,12 @@ pub fn items_with_name_in_module<'a>(
             local_query
         }
     };
-    let mut local_results = Vec::new();
-    // FIXME: This using module_symbols is likely wrong?
     local_query.search(&[sema.db.module_symbols(module)], |local_candidate| {
-        local_results.push(match local_candidate.def {
+        cb(match local_candidate.def {
             hir::ModuleDef::Macro(macro_def) => ItemInNs::Macros(macro_def),
             def => ItemInNs::from(def),
         })
-    });
-    local_results.into_iter()
+    })
 }
 
 fn find_items<'a>(
@@ -140,10 +141,10 @@ fn find_items<'a>(
     // Query the local crate using the symbol index.
     let mut local_results = Vec::new();
     local_query.search(&symbol_index::crate_symbols(db, krate), |local_candidate| {
-        local_results.push(match local_candidate.def {
+        ControlFlow::<()>::Continue(local_results.push(match local_candidate.def {
             hir::ModuleDef::Macro(macro_def) => ItemInNs::Macros(macro_def),
             def => ItemInNs::from(def),
-        })
+        }))
     });
     local_results.into_iter().chain(external_importables)
 }

src/tools/rust-analyzer/crates/ide-db/src/symbol_index.rs

@@ -25,6 +25,7 @@ use std::{
     fmt,
     hash::{Hash, Hasher},
     mem,
+    ops::ControlFlow,
 };
 
 use base_db::{
@@ -219,7 +220,7 @@ pub fn world_symbols(db: &RootDatabase, query: Query) -> Vec<FileSymbol> {
     };
 
     let mut res = vec![];
-    query.search(&indices, |f| res.push(f.clone()));
+    query.search::<()>(&indices, |f| ControlFlow::Continue(res.push(f.clone())));
     res
 }
 
@@ -313,11 +314,11 @@ impl SymbolIndex {
 }
 
 impl Query {
-    pub(crate) fn search<'sym>(
+    pub(crate) fn search<'sym, T>(
         self,
         indices: &'sym [Arc<SymbolIndex>],
-        cb: impl FnMut(&'sym FileSymbol),
-    ) {
+        cb: impl FnMut(&'sym FileSymbol) -> ControlFlow<T>,
+    ) -> Option<T> {
         let _p = tracing::info_span!("symbol_index::Query::search").entered();
         let mut op = fst::map::OpBuilder::new();
         match self.mode {
@@ -348,12 +349,12 @@ impl Query {
         }
     }
 
-    fn search_maps<'sym>(
+    fn search_maps<'sym, T>(
         &self,
         indices: &'sym [Arc<SymbolIndex>],
         mut stream: fst::map::Union<'_>,
-        mut cb: impl FnMut(&'sym FileSymbol),
-    ) {
+        mut cb: impl FnMut(&'sym FileSymbol) -> ControlFlow<T>,
+    ) -> Option<T> {
         let ignore_underscore_prefixed = !self.query.starts_with("__");
         while let Some((_, indexed_values)) = stream.next() {
             for &IndexedValue { index, value } in indexed_values {
@@ -379,11 +380,14 @@ impl Query {
                         continue;
                     }
                     if self.mode.check(&self.query, self.case_sensitive, symbol_name) {
-                        cb(symbol);
+                        if let Some(b) = cb(symbol).break_value() {
+                            return Some(b);
+                        }
                     }
                 }
             }
         }
+        None
     }
 
     fn matches_assoc_mode(&self, is_trait_assoc_item: bool) -> bool {