1 files changed, 194 insertions, 0 deletions

diff --git a/crates/ra_hir/src/module/imp.rs b/crates/ra_hir/src/module/imp.rs
new file mode 100644
index 000000000..76ea129a7
--- /dev/null
+++ b/crates/ra_hir/src/module/imp.rs
@@ -0,0 +1,194 @@
+use std::sync::Arc;
+
+use ra_syntax::{
+    ast::{self, NameOwner},
+    SmolStr,
+};
+use relative_path::RelativePathBuf;
+use rustc_hash::{FxHashMap, FxHashSet};
+use ra_db::{SourceRoot, SourceRootId, FileResolverImp, Cancelable, FileId,};
+
+use crate::{
+    HirDatabase,
+};
+
+use super::{
+    LinkData, LinkId, ModuleData, ModuleId, ModuleSource,
+    ModuleTree, Problem,
+};
+
+#[derive(Clone, Hash, PartialEq, Eq, Debug)]
+pub enum Submodule {
+    Declaration(SmolStr),
+    Definition(SmolStr, ModuleSource),
+}
+
+impl Submodule {
+    fn name(&self) -> &SmolStr {
+        match self {
+            Submodule::Declaration(name) => name,
+            Submodule::Definition(name, _) => name,
+        }
+    }
+}
+
+pub(crate) fn modules<'a>(
+    root: impl ast::ModuleItemOwner<'a>,
+) -> impl Iterator<Item = (SmolStr, ast::Module<'a>)> {
+    root.items()
+        .filter_map(|item| match item {
+            ast::ModuleItem::Module(m) => Some(m),
+            _ => None,
+        })
+        .filter_map(|module| {
+            let name = module.name()?.text();
+            Some((name, module))
+        })
+}
+
+pub(crate) fn module_tree(
+    db: &impl HirDatabase,
+    source_root: SourceRootId,
+) -> Cancelable<Arc<ModuleTree>> {
+    db.check_canceled()?;
+    let res = create_module_tree(db, source_root)?;
+    Ok(Arc::new(res))
+}
+
+fn create_module_tree<'a>(
+    db: &impl HirDatabase,
+    source_root: SourceRootId,
+) -> Cancelable<ModuleTree> {
+    let mut tree = ModuleTree::default();
+
+    let mut roots = FxHashMap::default();
+    let mut visited = FxHashSet::default();
+
+    let source_root = db.source_root(source_root);
+    for &file_id in source_root.files.iter() {
+        let source = ModuleSource::SourceFile(file_id);
+        if visited.contains(&source) {
+            continue; // TODO: use explicit crate_roots here
+        }
+        assert!(!roots.contains_key(&file_id));
+        let module_id = build_subtree(
+            db,
+            &source_root,
+            &mut tree,
+            &mut visited,
+            &mut roots,
+            None,
+            source,
+        )?;
+        roots.insert(file_id, module_id);
+    }
+    Ok(tree)
+}
+
+fn build_subtree(
+    db: &impl HirDatabase,
+    source_root: &SourceRoot,
+    tree: &mut ModuleTree,
+    visited: &mut FxHashSet<ModuleSource>,
+    roots: &mut FxHashMap<FileId, ModuleId>,
+    parent: Option<LinkId>,
+    source: ModuleSource,
+) -> Cancelable<ModuleId> {
+    visited.insert(source);
+    let id = tree.push_mod(ModuleData {
+        source,
+        parent,
+        children: Vec::new(),
+    });
+    for sub in db.submodules(source)?.iter() {
+        let link = tree.push_link(LinkData {
+            name: sub.name().clone(),
+            owner: id,
+            points_to: Vec::new(),
+            problem: None,
+        });
+
+        let (points_to, problem) = match sub {
+            Submodule::Declaration(name) => {
+                let (points_to, problem) =
+                    resolve_submodule(source, &name, &source_root.file_resolver);
+                let points_to = points_to
+                    .into_iter()
+                    .map(|file_id| match roots.remove(&file_id) {
+                        Some(module_id) => {
+                            tree.mods[module_id].parent = Some(link);
+                            Ok(module_id)
+                        }
+                        None => build_subtree(
+                            db,
+                            source_root,
+                            tree,
+                            visited,
+                            roots,
+                            Some(link),
+                            ModuleSource::SourceFile(file_id),
+                        ),
+                    })
+                    .collect::<Cancelable<Vec<_>>>()?;
+                (points_to, problem)
+            }
+            Submodule::Definition(_name, submodule_source) => {
+                let points_to = build_subtree(
+                    db,
+                    source_root,
+                    tree,
+                    visited,
+                    roots,
+                    Some(link),
+                    *submodule_source,
+                )?;
+                (vec![points_to], None)
+            }
+        };
+
+        tree.links[link].points_to = points_to;
+        tree.links[link].problem = problem;
+    }
+    Ok(id)
+}
+
+fn resolve_submodule(
+    source: ModuleSource,
+    name: &SmolStr,
+    file_resolver: &FileResolverImp,
+) -> (Vec<FileId>, Option<Problem>) {
+    let file_id = match source {
+        ModuleSource::SourceFile(it) => it,
+        ModuleSource::Module(..) => {
+            // TODO
+            return (Vec::new(), None);
+        }
+    };
+    let mod_name = file_resolver.file_stem(file_id);
+    let is_dir_owner = mod_name == "mod" || mod_name == "lib" || mod_name == "main";
+
+    let file_mod = RelativePathBuf::from(format!("../{}.rs", name));
+    let dir_mod = RelativePathBuf::from(format!("../{}/mod.rs", name));
+    let points_to: Vec<FileId>;
+    let problem: Option<Problem>;
+    if is_dir_owner {
+        points_to = [&file_mod, &dir_mod]
+            .iter()
+            .filter_map(|path| file_resolver.resolve(file_id, path))
+            .collect();
+        problem = if points_to.is_empty() {
+            Some(Problem::UnresolvedModule {
+                candidate: file_mod,
+            })
+        } else {
+            None
+        }
+    } else {
+        points_to = Vec::new();
+        problem = Some(Problem::NotDirOwner {
+            move_to: RelativePathBuf::from(format!("../{}/mod.rs", mod_name)),
+            candidate: file_mod,
+        });
+    }
+    (points_to, problem)
+}