6 files changed, 431 insertions, 0 deletions

diff --git a/crates/ra_db/src/file_resolver.rs b/crates/ra_db/src/file_resolver.rs
new file mode 100644
index 000000000..f849ac752
--- /dev/null
+++ b/crates/ra_db/src/file_resolver.rs
@@ -0,0 +1,76 @@
+use std::{
+    sync::Arc,
+    hash::{Hash, Hasher},
+    fmt,
+};
+
+use relative_path::RelativePath;
+
+use crate::input::FileId;
+
+pub trait FileResolver: fmt::Debug + Send + Sync + 'static {
+    fn file_stem(&self, file_id: FileId) -> String;
+    fn resolve(&self, file_id: FileId, path: &RelativePath) -> Option<FileId>;
+    fn debug_path(&self, _1file_id: FileId) -> Option<std::path::PathBuf> {
+        None
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct FileResolverImp {
+    inner: Arc<FileResolver>,
+}
+
+impl PartialEq for FileResolverImp {
+    fn eq(&self, other: &FileResolverImp) -> bool {
+        self.inner() == other.inner()
+    }
+}
+
+impl Eq for FileResolverImp {}
+
+impl Hash for FileResolverImp {
+    fn hash<H: Hasher>(&self, hasher: &mut H) {
+        self.inner().hash(hasher);
+    }
+}
+
+impl FileResolverImp {
+    pub fn new(inner: Arc<FileResolver>) -> FileResolverImp {
+        FileResolverImp { inner }
+    }
+    pub fn file_stem(&self, file_id: FileId) -> String {
+        self.inner.file_stem(file_id)
+    }
+    pub fn resolve(&self, file_id: FileId, path: &RelativePath) -> Option<FileId> {
+        self.inner.resolve(file_id, path)
+    }
+    pub fn debug_path(&self, file_id: FileId) -> Option<std::path::PathBuf> {
+        self.inner.debug_path(file_id)
+    }
+    fn inner(&self) -> *const FileResolver {
+        &*self.inner
+    }
+}
+
+impl Default for FileResolverImp {
+    fn default() -> FileResolverImp {
+        #[derive(Debug)]
+        struct DummyResolver;
+        impl FileResolver for DummyResolver {
+            fn file_stem(&self, _file_: FileId) -> String {
+                panic!("file resolver not set")
+            }
+            fn resolve(
+                &self,
+                _file_id: FileId,
+                _path: &::relative_path::RelativePath,
+            ) -> Option<FileId> {
+                panic!("file resolver not set")
+            }
+        }
+        FileResolverImp {
+            inner: Arc::new(DummyResolver),
+        }
+    }
+}
diff --git a/crates/ra_db/src/input.rs b/crates/ra_db/src/input.rs
new file mode 100644
index 000000000..9101ac7a8
--- /dev/null
+++ b/crates/ra_db/src/input.rs
@@ -0,0 +1,73 @@
+use std::sync::Arc;
+
+use rustc_hash::FxHashMap;
+use rustc_hash::FxHashSet;
+use salsa;
+
+use crate::file_resolver::FileResolverImp;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct FileId(pub u32);
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct CrateId(pub u32);
+
+#[derive(Debug, Clone, Default, PartialEq, Eq)]
+pub struct CrateGraph {
+    pub(crate) crate_roots: FxHashMap<CrateId, FileId>,
+}
+
+impl CrateGraph {
+    pub fn crate_root(&self, crate_id: CrateId) -> FileId {
+        self.crate_roots[&crate_id]
+    }
+    pub fn add_crate_root(&mut self, file_id: FileId) -> CrateId {
+        let crate_id = CrateId(self.crate_roots.len() as u32);
+        let prev = self.crate_roots.insert(crate_id, file_id);
+        assert!(prev.is_none());
+        crate_id
+    }
+    pub fn crate_id_for_crate_root(&self, file_id: FileId) -> Option<CrateId> {
+        let (&crate_id, _) = self
+            .crate_roots
+            .iter()
+            .find(|(_crate_id, &root_id)| root_id == file_id)?;
+        Some(crate_id)
+    }
+}
+
+salsa::query_group! {
+    pub trait FilesDatabase: salsa::Database {
+        fn file_text(file_id: FileId) -> Arc<String> {
+            type FileTextQuery;
+            storage input;
+        }
+        fn file_source_root(file_id: FileId) -> SourceRootId {
+            type FileSourceRootQuery;
+            storage input;
+        }
+        fn source_root(id: SourceRootId) -> Arc<SourceRoot> {
+            type SourceRootQuery;
+            storage input;
+        }
+        fn libraries() -> Arc<Vec<SourceRootId>> {
+            type LibrariesQuery;
+            storage input;
+        }
+        fn crate_graph() -> Arc<CrateGraph> {
+            type CrateGraphQuery;
+            storage input;
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct SourceRootId(pub u32);
+
+#[derive(Default, Clone, Debug, PartialEq, Eq)]
+pub struct SourceRoot {
+    pub file_resolver: FileResolverImp,
+    pub files: FxHashSet<FileId>,
+}
+
+pub const WORKSPACE: SourceRootId = SourceRootId(0);
diff --git a/crates/ra_db/src/lib.rs b/crates/ra_db/src/lib.rs
new file mode 100644
index 000000000..53805aada
--- /dev/null
+++ b/crates/ra_db/src/lib.rs
@@ -0,0 +1,83 @@
+//! ra_db defines basic database traits. Concrete DB is defined by ra_analysis.
+mod syntax_ptr;
+mod file_resolver;
+mod input;
+mod loc2id;
+pub mod mock;
+
+use std::sync::Arc;
+use ra_editor::LineIndex;
+use ra_syntax::{TextUnit, SourceFileNode};
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct Canceled;
+
+pub type Cancelable<T> = Result<T, Canceled>;
+
+impl std::fmt::Display for Canceled {
+    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        fmt.write_str("Canceled")
+    }
+}
+
+impl std::error::Error for Canceled {}
+
+pub use crate::{
+    syntax_ptr::LocalSyntaxPtr,
+    file_resolver::{FileResolver, FileResolverImp},
+    input::{
+        FilesDatabase, FileId, CrateId, SourceRoot, SourceRootId, CrateGraph, WORKSPACE,
+        FileTextQuery, FileSourceRootQuery, SourceRootQuery, LibrariesQuery, CrateGraphQuery,
+    },
+    loc2id::{LocationIntener, NumericId},
+};
+
+#[macro_export]
+macro_rules! impl_numeric_id {
+    ($id:ident) => {
+        impl $crate::NumericId for $id {
+            fn from_u32(id: u32) -> Self {
+                $id(id)
+            }
+            fn to_u32(self) -> u32 {
+                self.0
+            }
+        }
+    };
+}
+
+pub trait BaseDatabase: salsa::Database {
+    fn check_canceled(&self) -> Cancelable<()> {
+        if self.salsa_runtime().is_current_revision_canceled() {
+            Err(Canceled)
+        } else {
+            Ok(())
+        }
+    }
+}
+
+salsa::query_group! {
+    pub trait SyntaxDatabase: crate::input::FilesDatabase + BaseDatabase {
+        fn source_file(file_id: FileId) -> SourceFileNode {
+            type SourceFileQuery;
+        }
+        fn file_lines(file_id: FileId) -> Arc<LineIndex> {
+            type FileLinesQuery;
+        }
+    }
+}
+
+fn source_file(db: &impl SyntaxDatabase, file_id: FileId) -> SourceFileNode {
+    let text = db.file_text(file_id);
+    SourceFileNode::parse(&*text)
+}
+fn file_lines(db: &impl SyntaxDatabase, file_id: FileId) -> Arc<LineIndex> {
+    let text = db.file_text(file_id);
+    Arc::new(LineIndex::new(&*text))
+}
+
+#[derive(Clone, Copy, Debug)]
+pub struct FilePosition {
+    pub file_id: FileId,
+    pub offset: TextUnit,
+}
diff --git a/crates/ra_db/src/loc2id.rs b/crates/ra_db/src/loc2id.rs
new file mode 100644
index 000000000..69ba43d0f
--- /dev/null
+++ b/crates/ra_db/src/loc2id.rs
@@ -0,0 +1,100 @@
+use parking_lot::Mutex;
+
+use std::hash::Hash;
+
+use rustc_hash::FxHashMap;
+
+/// There are two principle ways to refer to things:
+///   - by their locatinon (module in foo/bar/baz.rs at line 42)
+///   - by their numeric id (module `ModuleId(42)`)
+///
+/// The first one is more powerful (you can actually find the thing in question
+/// by id), but the second one is so much more compact.
+///
+/// `Loc2IdMap` allows us to have a cake an eat it as well: by maintaining a
+/// bidirectional mapping between positional and numeric ids, we can use compact
+/// representation wich still allows us to get the actual item
+#[derive(Debug)]
+struct Loc2IdMap<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    loc2id: FxHashMap<LOC, ID>,
+    id2loc: FxHashMap<ID, LOC>,
+}
+
+impl<LOC, ID> Default for Loc2IdMap<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    fn default() -> Self {
+        Loc2IdMap {
+            loc2id: FxHashMap::default(),
+            id2loc: FxHashMap::default(),
+        }
+    }
+}
+
+impl<LOC, ID> Loc2IdMap<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    pub fn loc2id(&mut self, loc: &LOC) -> ID {
+        match self.loc2id.get(loc) {
+            Some(id) => return id.clone(),
+            None => (),
+        }
+        let id = self.loc2id.len();
+        assert!(id < u32::max_value() as usize);
+        let id = ID::from_u32(id as u32);
+        self.loc2id.insert(loc.clone(), id.clone());
+        self.id2loc.insert(id.clone(), loc.clone());
+        id
+    }
+
+    pub fn id2loc(&self, id: ID) -> LOC {
+        self.id2loc[&id].clone()
+    }
+}
+
+pub trait NumericId: Clone + Eq + Hash {
+    fn from_u32(id: u32) -> Self;
+    fn to_u32(self) -> u32;
+}
+
+#[derive(Debug)]
+pub struct LocationIntener<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    map: Mutex<Loc2IdMap<LOC, ID>>,
+}
+
+impl<LOC, ID> Default for LocationIntener<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    fn default() -> Self {
+        LocationIntener {
+            map: Default::default(),
+        }
+    }
+}
+
+impl<LOC, ID> LocationIntener<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    pub fn loc2id(&self, loc: &LOC) -> ID {
+        self.map.lock().loc2id(loc)
+    }
+    pub fn id2loc(&self, id: ID) -> LOC {
+        self.map.lock().id2loc(id)
+    }
+}
diff --git a/crates/ra_db/src/mock.rs b/crates/ra_db/src/mock.rs
new file mode 100644
index 000000000..2840f9655
--- /dev/null
+++ b/crates/ra_db/src/mock.rs
@@ -0,0 +1,51 @@
+use std::sync::Arc;
+
+use rustc_hash::FxHashSet;
+use relative_path::{RelativePath, RelativePathBuf};
+
+use crate::{FileId, FileResolver, SourceRoot, FileResolverImp};
+
+#[derive(Default, Debug)]
+pub struct FileMap(Vec<(FileId, RelativePathBuf)>);
+
+impl FileMap {
+    pub fn add(&mut self, path: RelativePathBuf) -> FileId {
+        let file_id = FileId((self.0.len() + 1) as u32);
+        self.0.push((file_id, path));
+        file_id
+    }
+
+    pub fn into_source_root(self) -> SourceRoot {
+        let files = self.files();
+        let file_resolver = FileResolverImp::new(Arc::new(self));
+        SourceRoot {
+            file_resolver,
+            files,
+        }
+    }
+
+    pub fn files(&self) -> FxHashSet<FileId> {
+        self.iter().map(|(id, _)| id).collect()
+    }
+
+    fn iter<'a>(&'a self) -> impl Iterator<Item = (FileId, &'a RelativePath)> + 'a {
+        self.0
+            .iter()
+            .map(|(id, path)| (*id, path.as_relative_path()))
+    }
+
+    fn path(&self, id: FileId) -> &RelativePath {
+        self.iter().find(|&(it, _)| it == id).unwrap().1
+    }
+}
+
+impl FileResolver for FileMap {
+    fn file_stem(&self, id: FileId) -> String {
+        self.path(id).file_stem().unwrap().to_string()
+    }
+    fn resolve(&self, id: FileId, rel: &RelativePath) -> Option<FileId> {
+        let path = self.path(id).join(rel).normalize();
+        let id = self.iter().find(|&(_, p)| path == p)?.0;
+        Some(id)
+    }
+}
diff --git a/crates/ra_db/src/syntax_ptr.rs b/crates/ra_db/src/syntax_ptr.rs
new file mode 100644
index 000000000..dac94dd36
--- /dev/null
+++ b/crates/ra_db/src/syntax_ptr.rs
@@ -0,0 +1,48 @@
+use ra_syntax::{SourceFileNode, SyntaxKind, SyntaxNode, SyntaxNodeRef, TextRange};
+
+/// A pionter to a syntax node inside a file.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct LocalSyntaxPtr {
+    range: TextRange,
+    kind: SyntaxKind,
+}
+
+impl LocalSyntaxPtr {
+    pub fn new(node: SyntaxNodeRef) -> LocalSyntaxPtr {
+        LocalSyntaxPtr {
+            range: node.range(),
+            kind: node.kind(),
+        }
+    }
+
+    pub fn resolve(self, file: &SourceFileNode) -> SyntaxNode {
+        let mut curr = file.syntax();
+        loop {
+            if curr.range() == self.range && curr.kind() == self.kind {
+                return curr.owned();
+            }
+            curr = curr
+                .children()
+                .find(|it| self.range.is_subrange(&it.range()))
+                .unwrap_or_else(|| panic!("can't resolve local ptr to SyntaxNode: {:?}", self))
+        }
+    }
+
+    pub fn range(self) -> TextRange {
+        self.range
+    }
+}
+
+#[test]
+fn test_local_syntax_ptr() {
+    use ra_syntax::{ast, AstNode};
+    let file = SourceFileNode::parse("struct Foo { f: u32, }");
+    let field = file
+        .syntax()
+        .descendants()
+        .find_map(ast::NamedFieldDef::cast)
+        .unwrap();
+    let ptr = LocalSyntaxPtr::new(field.syntax());
+    let field_syntax = ptr.resolve(&file);
+    assert_eq!(field.syntax(), field_syntax);
+}