2 files changed, 237 insertions, 0 deletions

diff --git a/crates/ra_analysis/src/db/imp.rs b/crates/ra_analysis/src/db/imp.rs
new file mode 100644
index 000000000..f26be1046
--- /dev/null
+++ b/crates/ra_analysis/src/db/imp.rs
@@ -0,0 +1,152 @@
+use std::{
+    sync::Arc,
+    any::Any,
+    hash::{Hash, Hasher},
+    collections::hash_map::{DefaultHasher, HashMap},
+    iter,
+};
+use salsa;
+use {FileId, imp::FileResolverImp};
+use super::{State, Query, QueryCtx};
+
+pub(super) type Data = Arc<Any + Send + Sync + 'static>;
+
+#[derive(Debug)]
+pub(super) struct Db {
+    names: Arc<HashMap<salsa::QueryTypeId, &'static str>>,
+    pub(super) imp: salsa::Db<State, Data>,
+}
+
+impl Db {
+    pub(super) fn new(mut reg: QueryRegistry) -> Db {
+        let config = reg.config.take().unwrap();
+        Db {
+            names: Arc::new(reg.names),
+            imp: salsa::Db::new(config, State::default())
+        }
+    }
+    pub(crate) fn with_changes(&self, new_state: State, changed_files: &[FileId], resolver_changed: bool) -> Db {
+        let names = self.names.clone();
+        let mut invalidations = salsa::Invalidations::new();
+        invalidations.invalidate(FILE_TEXT, changed_files.iter().map(hash).map(salsa::InputFingerprint));
+        if resolver_changed {
+            invalidations.invalidate(FILE_SET, iter::once(salsa::InputFingerprint(hash(&()))));
+        } else {
+            invalidations.invalidate(FILE_SET, iter::empty());
+        }
+        let imp = self.imp.with_ground_data(
+            new_state,
+            invalidations,
+        );
+        Db { names, imp }
+    }
+    pub(super) fn extract_trace(&self, ctx: &salsa::QueryCtx<State, Data>) -> Vec<&'static str> {
+        ctx.trace().into_iter().map(|it| self.names[&it]).collect()
+    }
+}
+
+pub(crate) trait EvalQuery {
+    type Params;
+    type Output;
+    fn query_type(&self) -> salsa::QueryTypeId;
+    fn f(&self) -> salsa::QueryFn<State, Data>;
+    fn get(&self, &QueryCtx, Self::Params) -> Arc<Self::Output>;
+}
+
+impl<T, R> EvalQuery for Query<T, R>
+where
+    T: Hash + Send + Sync + 'static,
+    R: Hash + Send + Sync + 'static,
+{
+    type Params = T;
+    type Output = R;
+    fn query_type(&self) -> salsa::QueryTypeId {
+        salsa::QueryTypeId(self.0)
+    }
+    fn f(&self) -> salsa::QueryFn<State, Data> {
+        let f = self.1;
+        Box::new(move |ctx, data| {
+            let ctx = QueryCtx { imp: ctx };
+            let data: &T = data.downcast_ref().unwrap();
+            let res = f(ctx, data);
+            let h = hash(&res);
+            (Arc::new(res), salsa::OutputFingerprint(h))
+        })
+    }
+    fn get(&self, ctx: &QueryCtx, params: Self::Params) -> Arc<Self::Output> {
+        let query_id = salsa::QueryId(
+            self.query_type(),
+            salsa::InputFingerprint(hash(&params)),
+        );
+        let res = ctx.imp.get(query_id, Arc::new(params));
+        res.downcast().unwrap()
+    }
+}
+
+pub(super) struct QueryRegistry {
+    config: Option<salsa::QueryConfig<State, Data>>,
+    names: HashMap<salsa::QueryTypeId, &'static str>,
+}
+
+impl QueryRegistry {
+    pub(super) fn new() -> QueryRegistry {
+        let mut config = salsa::QueryConfig::<State, Data>::new();
+        config = config.with_ground_query(
+            FILE_TEXT, Box::new(|state, params| {
+                let file_id: &FileId = params.downcast_ref().unwrap();
+                let res = state.file_map[file_id].clone();
+                let fingerprint = salsa::OutputFingerprint(hash(&res));
+                (res, fingerprint)
+            })
+        );
+        config = config.with_ground_query(
+            FILE_SET, Box::new(|state, _params| {
+                let file_ids: Vec<FileId> = state.file_map.keys().cloned().collect();
+                let hash = hash(&file_ids);
+                let file_resolver = state.file_resolver.clone();
+                let res = (file_ids, file_resolver);
+                let fingerprint = salsa::OutputFingerprint(hash);
+                (Arc::new(res), fingerprint)
+            })
+        );
+        let mut names = HashMap::new();
+        names.insert(FILE_TEXT, "FILE_TEXT");
+        names.insert(FILE_SET, "FILE_SET");
+        QueryRegistry { config: Some(config), names }
+    }
+    pub(super) fn add<Q: EvalQuery>(&mut self, q: Q, name: &'static str) {
+        let id = q.query_type();
+        let prev = self.names.insert(id, name);
+        assert!(prev.is_none(), "duplicate query: {:?}", id);
+        let config = self.config.take().unwrap();
+        let config = config.with_query(id, q.f());
+        self.config= Some(config);
+    }
+}
+
+fn hash<T: Hash>(x: &T) -> u64 {
+    let mut hasher = DefaultHasher::new();
+    x.hash(&mut hasher);
+    hasher.finish()
+}
+
+const FILE_TEXT: salsa::QueryTypeId = salsa::QueryTypeId(0);
+pub(super) fn file_text(ctx: QueryCtx, file_id: FileId) -> Arc<String> {
+    let query_id = salsa::QueryId(
+        FILE_TEXT,
+        salsa::InputFingerprint(hash(&file_id)),
+    );
+    let res = ctx.imp.get(query_id, Arc::new(file_id));
+    res.downcast().unwrap()
+}
+
+const FILE_SET: salsa::QueryTypeId = salsa::QueryTypeId(1);
+pub(super) fn file_set(ctx: QueryCtx) -> Arc<(Vec<FileId>, FileResolverImp)> {
+    let query_id = salsa::QueryId(
+        FILE_SET,
+        salsa::InputFingerprint(hash(&())),
+    );
+    let res = ctx.imp.get(query_id, Arc::new(()));
+    res.downcast().unwrap()
+}
+
diff --git a/crates/ra_analysis/src/db/mod.rs b/crates/ra_analysis/src/db/mod.rs
new file mode 100644
index 000000000..22769d112
--- /dev/null
+++ b/crates/ra_analysis/src/db/mod.rs
@@ -0,0 +1,85 @@
+mod imp;
+
+use std::{
+    sync::Arc,
+};
+use im;
+use salsa;
+use {FileId, imp::FileResolverImp};
+
+#[derive(Debug, Default, Clone)]
+pub(crate) struct State {
+    pub(crate) file_map: im::HashMap<FileId, Arc<String>>,
+    pub(crate) file_resolver: FileResolverImp
+}
+
+#[derive(Debug)]
+pub(crate) struct Db {
+    imp: imp::Db,
+}
+
+#[derive(Clone, Copy)]
+pub(crate) struct QueryCtx<'a> {
+    imp: &'a salsa::QueryCtx<State, imp::Data>,
+}
+
+pub(crate) struct Query<T, R>(pub(crate) u16, pub(crate) fn(QueryCtx, &T) -> R);
+
+pub(crate) struct QueryRegistry {
+    imp: imp::QueryRegistry,
+}
+
+impl Default for Db {
+    fn default() -> Db {
+        Db::new()
+    }
+}
+
+impl Db {
+    pub(crate) fn new() -> Db {
+        let reg = QueryRegistry::new();
+        Db { imp: imp::Db::new(reg.imp) }
+    }
+    pub(crate) fn state(&self) -> &State {
+        self.imp.imp.ground_data()
+    }
+    pub(crate) fn with_changes(&self, new_state: State, changed_files: &[FileId], resolver_changed: bool) -> Db {
+        Db { imp: self.imp.with_changes(new_state, changed_files, resolver_changed) }
+    }
+    pub(crate) fn make_query<F: FnOnce(QueryCtx) -> R, R>(&self, f: F) -> R {
+        let ctx = QueryCtx { imp: &self.imp.imp.query_ctx() };
+        f(ctx)
+    }
+    #[allow(unused)]
+    pub(crate) fn trace_query<F: FnOnce(QueryCtx) -> R, R>(&self, f: F) -> (R, Vec<&'static str>) {
+        let ctx = QueryCtx { imp: &self.imp.imp.query_ctx() };
+        let res = f(ctx);
+        let trace = self.imp.extract_trace(ctx.imp);
+        (res, trace)
+    }
+}
+
+impl<'a> QueryCtx<'a> {
+    pub(crate) fn get<Q: imp::EvalQuery>(&self, q: Q, params: Q::Params) -> Arc<Q::Output> {
+        q.get(self, params)
+    }
+}
+
+pub(crate) fn file_text(ctx: QueryCtx, file_id: FileId) -> Arc<String> {
+    imp::file_text(ctx, file_id)
+}
+
+pub(crate) fn file_set(ctx: QueryCtx) -> Arc<(Vec<FileId>, FileResolverImp)> {
+    imp::file_set(ctx)
+}
+impl QueryRegistry {
+    fn new() -> QueryRegistry {
+        let mut reg = QueryRegistry { imp: imp::QueryRegistry::new() };
+        ::queries::register_queries(&mut reg);
+        ::module_map::register_queries(&mut reg);
+        reg
+    }
+    pub(crate) fn add<Q: imp::EvalQuery>(&mut self, q: Q, name: &'static str) {
+        self.imp.add(q, name)
+    }
+}