Initial auto import action implementation

3 files changed, 102 insertions, 3 deletions

diff --git a/crates/ra_ide/src/assists.rs b/crates/ra_ide/src/assists.rs
index a936900da..c43c45c65 100644
--- a/crates/ra_ide/src/assists.rs
+++ b/crates/ra_ide/src/assists.rs
@@ -2,8 +2,9 @@
 
 use ra_db::{FilePosition, FileRange};
 
-use crate::{db::RootDatabase, FileId, SourceChange, SourceFileEdit};
-
+use crate::{
+    db::RootDatabase, imports_locator::ImportsLocatorIde, FileId, SourceChange, SourceFileEdit,
+};
 use either::Either;
 pub use ra_assists::AssistId;
 use ra_assists::{AssistAction, AssistLabel};
@@ -16,7 +17,7 @@ pub struct Assist {
 }
 
 pub(crate) fn assists(db: &RootDatabase, frange: FileRange) -> Vec<Assist> {
-    ra_assists::assists(db, frange)
+    ra_assists::assists_with_imports_locator(db, frange, ImportsLocatorIde::new(db))
         .into_iter()
         .map(|assist| {
             let file_id = frange.file_id;
diff --git a/crates/ra_ide/src/imports_locator.rs b/crates/ra_ide/src/imports_locator.rs
new file mode 100644
index 000000000..23391ac3b
--- /dev/null
+++ b/crates/ra_ide/src/imports_locator.rs
@@ -0,0 +1,97 @@
+//! This module contains an import search funcionality that is provided to the ra_assists module.
+//! Later, this should be moved away to a separate crate that is accessible from the ra_assists module.
+
+use crate::{
+    db::RootDatabase,
+    references::{classify_name, classify_name_ref, NameDefinition, NameKind},
+    symbol_index::{self, FileSymbol},
+    Query,
+};
+use ast::NameRef;
+use hir::{db::HirDatabase, InFile, ModPath, Module, SourceBinder};
+use itertools::Itertools;
+use ra_assists::ImportsLocator;
+use ra_prof::profile;
+use ra_syntax::{ast, AstNode, SyntaxKind::NAME};
+
+pub(crate) struct ImportsLocatorIde<'a> {
+    source_binder: SourceBinder<'a, RootDatabase>,
+}
+
+impl<'a> ImportsLocatorIde<'a> {
+    pub(crate) fn new(db: &'a RootDatabase) -> Self {
+        Self { source_binder: SourceBinder::new(db) }
+    }
+
+    fn search_for_imports(
+        &mut self,
+        name_to_import: &ast::NameRef,
+        module_with_name_to_import: Module,
+    ) -> Vec<ModPath> {
+        let _p = profile("search_for_imports");
+        let db = self.source_binder.db;
+        let name_to_import = name_to_import.text();
+
+        let project_results = {
+            let mut query = Query::new(name_to_import.to_string());
+            query.exact();
+            query.limit(10);
+            symbol_index::world_symbols(db, query)
+        };
+        let lib_results = {
+            let mut query = Query::new(name_to_import.to_string());
+            query.libs();
+            query.exact();
+            query.limit(10);
+            symbol_index::world_symbols(db, query)
+        };
+
+        project_results
+            .into_iter()
+            .chain(lib_results.into_iter())
+            .filter_map(|import_candidate| self.get_name_definition(db, &import_candidate))
+            .filter_map(|name_definition_to_import| {
+                if let NameKind::Def(module_def) = name_definition_to_import.kind {
+                    module_with_name_to_import.find_use_path(db, module_def)
+                } else {
+                    None
+                }
+            })
+            .filter(|use_path| !use_path.segments.is_empty())
+            .unique()
+            .collect()
+    }
+
+    fn get_name_definition(
+        &mut self,
+        db: &impl HirDatabase,
+        import_candidate: &FileSymbol,
+    ) -> Option<NameDefinition> {
+        let _p = profile("get_name_definition");
+        let file_id = import_candidate.file_id.into();
+        let candidate_node = import_candidate.ptr.to_node(&db.parse_or_expand(file_id)?);
+        let candidate_name_node = if candidate_node.kind() != NAME {
+            candidate_node.children().find(|it| it.kind() == NAME)?
+        } else {
+            candidate_node
+        };
+        classify_name(
+            &mut self.source_binder,
+            hir::InFile { file_id, value: &ast::Name::cast(candidate_name_node)? },
+        )
+    }
+}
+
+impl<'a> ImportsLocator<'a> for ImportsLocatorIde<'a> {
+    fn find_imports(
+        &mut self,
+        name_to_import: InFile<&NameRef>,
+        module_with_name_to_import: Module,
+    ) -> Option<Vec<ModPath>> {
+        if classify_name_ref(&mut self.source_binder, name_to_import).is_none() {
+            Some(self.search_for_imports(name_to_import.value, module_with_name_to_import))
+        } else {
+            None
+        }
+    }
+}
diff --git a/crates/ra_ide/src/lib.rs b/crates/ra_ide/src/lib.rs
index 62fe6d2a9..03ad6b2c1 100644
--- a/crates/ra_ide/src/lib.rs
+++ b/crates/ra_ide/src/lib.rs
@@ -30,6 +30,7 @@ mod syntax_highlighting;
 mod parent_module;
 mod references;
 mod impls;
+mod imports_locator;
 mod assists;
 mod diagnostics;
 mod syntax_tree;