4 files changed, 84 insertions, 6 deletions

diff --git a/crates/ra_analysis/src/completion.rs b/crates/ra_analysis/src/completion.rs
new file mode 100644
index 000000000..a0fd6828d
--- /dev/null
+++ b/crates/ra_analysis/src/completion.rs
@@ -0,0 +1,61 @@
+use ra_editor::{CompletionItem, find_node_at_offset, complete_module_items};
+use ra_syntax::{
+    AtomEdit, File, TextUnit, AstNode,
+    ast::{self, ModuleItemOwner},
+};
+
+use crate::{
+    FileId, Cancelable,
+    db::{self, SyntaxDatabase},
+    descriptors::module::{ModulesDatabase, ModuleTree, ModuleId},
+};
+
+pub(crate) fn resolve_based_completion(db: &db::RootDatabase, file_id: FileId, offset: TextUnit) -> Cancelable<Option<Vec<CompletionItem>>> {
+    let file = db.file_syntax(file_id);
+    let module_tree = db.module_tree()?;
+    let file = {
+        let edit = AtomEdit::insert(offset, "intellijRulezz".to_string());
+        file.reparse(&edit)
+    };
+    let target_file = match find_target_module(&module_tree, file_id, &file, offset) {
+        None => return Ok(None),
+        Some(target_module) => {
+            let file_id = target_module.file_id(&module_tree);
+            db.file_syntax(file_id)
+        }
+    };
+    let mut res = Vec::new();
+    complete_module_items(target_file.ast().items(), None, &mut res);
+    Ok(Some(res))
+}
+
+pub(crate) fn find_target_module(module_tree: &ModuleTree, file_id: FileId, file: &File, offset: TextUnit) -> Option<ModuleId> {
+    let name_ref: ast::NameRef = find_node_at_offset(file.syntax(), offset)?;
+    let mut crate_path = crate_path(name_ref)?;
+    let module_id = module_tree.any_module_for_file(file_id)?;
+    crate_path.pop();
+    let mut target_module = module_id.root(&module_tree);
+    for name in crate_path {
+        target_module = target_module.child(module_tree, name.text().as_str())?;
+    }
+    Some(target_module)
+}
+
+fn crate_path(name_ref: ast::NameRef) -> Option<Vec<ast::NameRef>> {
+    let mut path = name_ref.syntax()
+        .parent().and_then(ast::PathSegment::cast)?
+        .parent_path();
+    let mut res = Vec::new();
+    loop {
+        let segment = path.segment()?;
+        match segment.kind()? {
+            ast::PathSegmentKind::Name(name) => res.push(name),
+            ast::PathSegmentKind::CrateKw => break,
+            ast::PathSegmentKind::SelfKw | ast::PathSegmentKind::SuperKw =>
+                return None,
+        }
+        path = path.qualifier()?;
+    }
+    res.reverse();
+    Some(res)
+}
diff --git a/crates/ra_analysis/src/imp.rs b/crates/ra_analysis/src/imp.rs
index f142b6c43..f3e5b2887 100644
--- a/crates/ra_analysis/src/imp.rs
+++ b/crates/ra_analysis/src/imp.rs
@@ -5,7 +5,7 @@ use std::{
     sync::Arc,
 };
 
-use ra_editor::{self, find_node_at_offset, resolve_local_name, FileSymbol, LineIndex, LocalEdit};
+use ra_editor::{self, find_node_at_offset, resolve_local_name, FileSymbol, LineIndex, LocalEdit, CompletionItem};
 use ra_syntax::{
     ast::{self, ArgListOwner, Expr, NameOwner},
     AstNode, File, SmolStr,
@@ -197,6 +197,26 @@ impl AnalysisImpl {
     pub fn crate_root(&self, crate_id: CrateId) -> FileId {
         self.data.crate_graph.crate_roots[&crate_id]
     }
+    pub fn completions(&self, file_id: FileId, offset: TextUnit) -> Cancelable<Option<Vec<CompletionItem>>> {
+        let mut res = Vec::new();
+        let mut has_completions = false;
+        let file = self.file_syntax(file_id);
+        if let Some(scope_based) = ra_editor::scope_completion(&file, offset) {
+            res.extend(scope_based);
+            has_completions = true;
+        }
+        let root = self.root(file_id);
+        if let Some(scope_based) = crate::completion::resolve_based_completion(root.db(), file_id, offset)? {
+            res.extend(scope_based);
+            has_completions = true;
+        }
+        let res = if has_completions {
+            Some(res)
+        } else {
+            None
+        };
+        Ok(res)
+    }
     pub fn approximately_resolve_symbol(
         &self,
         file_id: FileId,
diff --git a/crates/ra_analysis/src/lib.rs b/crates/ra_analysis/src/lib.rs
index 67a239a5c..7078e2d31 100644
--- a/crates/ra_analysis/src/lib.rs
+++ b/crates/ra_analysis/src/lib.rs
@@ -11,6 +11,7 @@ mod descriptors;
 mod imp;
 mod roots;
 mod symbol_index;
+mod completion;
 
 use std::{fmt::Debug, sync::Arc};
 
@@ -246,8 +247,7 @@ impl Analysis {
         Ok(ra_editor::highlight(&file))
     }
     pub fn completions(&self, file_id: FileId, offset: TextUnit) -> Cancelable<Option<Vec<CompletionItem>>> {
-        let file = self.imp.file_syntax(file_id);
-        Ok(ra_editor::scope_completion(&file, offset))
+        self.imp.completions(file_id, offset)
     }
     pub fn assists(&self, file_id: FileId, range: TextRange) -> Cancelable<Vec<SourceChange>> {
         Ok(self.imp.assists(file_id, range))
diff --git a/crates/ra_analysis/src/roots.rs b/crates/ra_analysis/src/roots.rs
index aa0243720..1e9e613ac 100644
--- a/crates/ra_analysis/src/roots.rs
+++ b/crates/ra_analysis/src/roots.rs
@@ -1,7 +1,5 @@
 use std::{sync::Arc};
 
-use ra_editor::LineIndex;
-use ra_syntax::File;
 use rustc_hash::FxHashSet;
 use rayon::prelude::*;
 use salsa::Database;
@@ -10,7 +8,6 @@ use crate::{
     Cancelable,
     db::{self, FilesDatabase, SyntaxDatabase},
     imp::FileResolverImp,
-    descriptors::module::{ModulesDatabase, ModuleTree},
     symbol_index::SymbolIndex,
     FileId,
 };