Merge #429

429: Reorganize hir public API in terms of code model r=matklad a=matklad

Recently, I've been thinking about introducing "object orient code model" API for rust: a set of APIs with types like `Function`, `Module`, etc, with methods like `get_containing_declaration()`, `get_type()`, etc. 

Here's how a similar API might look like in .Net land:

https://docs.microsoft.com/en-us/dotnet/api/microsoft.codeanalysis.semanticmodel?view=roslyn-dotnet

https://docs.microsoft.com/en-us/dotnet/api/microsoft.codeanalysis.imethodsymbol?view=roslyn-dotnet

The main feature of such API is that it can be powered by different backends. For example, one can imagine a backend based on salsa, and a backend which reads all the data from a specially prepared JSON file. The "OO" bit is interesting mostly in this "can swap implementations via dynamic dispatch" aspect, the actual API could have a more database/ECS flavored feeling.

It's not clear at this moment how exactly should we implement such a dynamically (or if we even need dynamism in the first pace) swapable API in Rust, but I'd love to experiment with this a bit. 

For starters, I propose creating a `code_model_api` which contains various definition types and their public methods (mandatory implemented as one-liners, so that the API has a header-file feel). Specifically, I propose that each type is a wrapper around some integer ID, and that all methods of it accept a `&db` argument.  The actual impl goes elsewhere: into the db queries or, absent a better place, into the `code_model_api_impl`. In the first commit, I've moved the simplest type, `Crate`, over to this pattern.

I *think* that we, at least initially, will be used types from `code_model_api` *inside* `hir` as well, but this is not required: we might pick a different implementation down the line, while preserving the API. 

Long term I'd love to replace the `db: &impl HirDatabase` argument by a `mp: &dyn ModelProvider`, implement `ModelProvider` for `T: HirDatabase`, and move `code_model_api` into the separate crate, which does not depend on `hir`. 

@flodiebold you've recently done some `Def`s work, would do you think of this plan? Could it become a good API in the future, or is it just a useless boilerplate duplicating method signatures between `code_model_api` and `code_model_impl`?


Co-authored-by: Aleksey Kladov <[email protected]>

1 files changed, 273 insertions, 0 deletions

diff --git a/crates/ra_hir/src/nameres/tests.rs b/crates/ra_hir/src/nameres/tests.rs
new file mode 100644
index 000000000..dcbe65aec
--- /dev/null
+++ b/crates/ra_hir/src/nameres/tests.rs
@@ -0,0 +1,273 @@
+use std::sync::Arc;
+
+use salsa::Database;
+use ra_db::{FilesDatabase, CrateGraph};
+use relative_path::RelativePath;
+use test_utils::assert_eq_text;
+
+use crate::{
+    self as hir,
+    db::HirDatabase,
+    mock::MockDatabase,
+};
+
+fn item_map(fixture: &str) -> (Arc<hir::ItemMap>, hir::ModuleId) {
+    let (db, pos) = MockDatabase::with_position(fixture);
+    let source_root = db.file_source_root(pos.file_id);
+    let module = hir::source_binder::module_from_position(&db, pos)
+        .unwrap()
+        .unwrap();
+    let module_id = module.def_id.loc(&db).module_id;
+    (db.item_map(source_root).unwrap(), module_id)
+}
+
+fn check_module_item_map(map: &hir::ItemMap, module_id: hir::ModuleId, expected: &str) {
+    let mut lines = map.per_module[&module_id]
+        .items
+        .iter()
+        .map(|(name, res)| format!("{}: {}", name, dump_resolution(res)))
+        .collect::<Vec<_>>();
+    lines.sort();
+    let actual = lines.join("\n");
+    let expected = expected
+        .trim()
+        .lines()
+        .map(|it| it.trim())
+        .collect::<Vec<_>>()
+        .join("\n");
+    assert_eq_text!(&actual, &expected);
+
+    fn dump_resolution(resolution: &hir::Resolution) -> &'static str {
+        match (
+            resolution.def_id.types.is_some(),
+            resolution.def_id.values.is_some(),
+        ) {
+            (true, true) => "t v",
+            (true, false) => "t",
+            (false, true) => "v",
+            (false, false) => "_",
+        }
+    }
+}
+
+#[test]
+fn item_map_smoke_test() {
+    let (item_map, module_id) = item_map(
+        "
+        //- /lib.rs
+        mod foo;
+
+        use crate::foo::bar::Baz;
+        <|>
+
+        //- /foo/mod.rs
+        pub mod bar;
+
+        //- /foo/bar.rs
+        pub struct Baz;
+    ",
+    );
+    check_module_item_map(
+        &item_map,
+        module_id,
+        "
+            Baz: t v
+            foo: t
+        ",
+    );
+}
+
+#[test]
+fn item_map_contains_items_from_expansions() {
+    let (item_map, module_id) = item_map(
+        "
+        //- /lib.rs
+        mod foo;
+
+        use crate::foo::bar::Baz;
+        <|>
+
+        //- /foo/mod.rs
+        pub mod bar;
+
+        //- /foo/bar.rs
+        salsa::query_group! {
+            trait Baz {}
+        }
+    ",
+    );
+    check_module_item_map(
+        &item_map,
+        module_id,
+        "
+            Baz: t
+            foo: t
+        ",
+    );
+}
+
+#[test]
+fn item_map_using_self() {
+    let (item_map, module_id) = item_map(
+        "
+            //- /lib.rs
+            mod foo;
+            use crate::foo::bar::Baz::{self};
+            <|>
+            //- /foo/mod.rs
+            pub mod bar;
+            //- /foo/bar.rs
+            pub struct Baz;
+        ",
+    );
+    check_module_item_map(
+        &item_map,
+        module_id,
+        "
+            Baz: t v
+            foo: t
+        ",
+    );
+}
+
+#[test]
+fn item_map_across_crates() {
+    let (mut db, sr) = MockDatabase::with_files(
+        "
+        //- /main.rs
+        use test_crate::Baz;
+
+        //- /lib.rs
+        pub struct Baz;
+    ",
+    );
+    let main_id = sr.files[RelativePath::new("/main.rs")];
+    let lib_id = sr.files[RelativePath::new("/lib.rs")];
+
+    let mut crate_graph = CrateGraph::default();
+    let main_crate = crate_graph.add_crate_root(main_id);
+    let lib_crate = crate_graph.add_crate_root(lib_id);
+    crate_graph.add_dep(main_crate, "test_crate".into(), lib_crate);
+
+    db.set_crate_graph(crate_graph);
+
+    let source_root = db.file_source_root(main_id);
+    let module = hir::source_binder::module_from_file_id(&db, main_id)
+        .unwrap()
+        .unwrap();
+    let module_id = module.def_id.loc(&db).module_id;
+    let item_map = db.item_map(source_root).unwrap();
+
+    check_module_item_map(
+        &item_map,
+        module_id,
+        "
+            Baz: t v
+            test_crate: t
+        ",
+    );
+}
+
+#[test]
+fn typing_inside_a_function_should_not_invalidate_item_map() {
+    let (mut db, pos) = MockDatabase::with_position(
+        "
+        //- /lib.rs
+        mod foo;
+
+        use crate::foo::bar::Baz;
+
+        //- /foo/mod.rs
+        pub mod bar;
+
+        //- /foo/bar.rs
+        <|>
+        salsa::query_group! {
+            trait Baz {
+                fn foo() -> i32 { 1 + 1 }
+            }
+        }
+        ",
+    );
+    let source_root = db.file_source_root(pos.file_id);
+    {
+        let events = db.log_executed(|| {
+            db.item_map(source_root).unwrap();
+        });
+        assert!(format!("{:?}", events).contains("item_map"))
+    }
+
+    let new_text = "
+        salsa::query_group! {
+            trait Baz {
+                fn foo() -> i32 { 92 }
+            }
+        }
+    "
+    .to_string();
+
+    db.query_mut(ra_db::FileTextQuery)
+        .set(pos.file_id, Arc::new(new_text));
+
+    {
+        let events = db.log_executed(|| {
+            db.item_map(source_root).unwrap();
+        });
+        assert!(
+            !format!("{:?}", events).contains("item_map"),
+            "{:#?}",
+            events
+        )
+    }
+}
+
+#[test]
+fn typing_inside_a_function_inside_a_macro_should_not_invalidate_item_map() {
+    let (mut db, pos) = MockDatabase::with_position(
+        "
+        //- /lib.rs
+        mod foo;<|>
+
+        use crate::foo::bar::Baz;
+
+        fn foo() -> i32 {
+            1 + 1
+        }
+        //- /foo/mod.rs
+        pub mod bar;
+
+        //- /foo/bar.rs
+        pub struct Baz;
+    ",
+    );
+    let source_root = db.file_source_root(pos.file_id);
+    {
+        let events = db.log_executed(|| {
+            db.item_map(source_root).unwrap();
+        });
+        assert!(format!("{:?}", events).contains("item_map"))
+    }
+
+    let new_text = "
+        mod foo;
+
+        use crate::foo::bar::Baz;
+
+        fn foo() -> i32 { 92 }
+    "
+    .to_string();
+
+    db.query_mut(ra_db::FileTextQuery)
+        .set(pos.file_id, Arc::new(new_text));
+
+    {
+        let events = db.log_executed(|| {
+            db.item_map(source_root).unwrap();
+        });
+        assert!(
+            !format!("{:?}", events).contains("item_map"),
+            "{:#?}",
+            events
+        )
+    }
+}