rust/crates/ra_hir_def/src/import_map.rs
2020-06-05 14:24:51 +02:00

332 lines
8.8 KiB
Rust

//! A map of all publicly exported items in a crate.
use std::{collections::hash_map::Entry, fmt, sync::Arc};
use ra_db::CrateId;
use rustc_hash::FxHashMap;
use crate::{
db::DefDatabase,
item_scope::ItemInNs,
path::{ModPath, PathKind},
visibility::Visibility,
ModuleDefId, ModuleId,
};
/// A map from publicly exported items to the path needed to import/name them from a downstream
/// crate.
///
/// Reexports of items are taken into account, ie. if something is exported under multiple
/// names, the one with the shortest import path will be used.
///
/// Note that all paths are relative to the containing crate's root, so the crate name still needs
/// to be prepended to the `ModPath` before the path is valid.
#[derive(Eq, PartialEq)]
pub struct ImportMap {
map: FxHashMap<ItemInNs, ModPath>,
}
impl ImportMap {
pub fn import_map_query(db: &dyn DefDatabase, krate: CrateId) -> Arc<Self> {
let _p = ra_prof::profile("import_map_query");
let def_map = db.crate_def_map(krate);
let mut import_map = FxHashMap::with_capacity_and_hasher(64, Default::default());
// We look only into modules that are public(ly reexported), starting with the crate root.
let empty = ModPath { kind: PathKind::Plain, segments: vec![] };
let root = ModuleId { krate, local_id: def_map.root };
let mut worklist = vec![(root, empty)];
while let Some((module, mod_path)) = worklist.pop() {
let ext_def_map;
let mod_data = if module.krate == krate {
&def_map[module.local_id]
} else {
// The crate might reexport a module defined in another crate.
ext_def_map = db.crate_def_map(module.krate);
&ext_def_map[module.local_id]
};
let visible_items = mod_data.scope.entries().filter_map(|(name, per_ns)| {
let per_ns = per_ns.filter_visibility(|vis| vis == Visibility::Public);
if per_ns.is_none() {
None
} else {
Some((name, per_ns))
}
});
for (name, per_ns) in visible_items {
let mk_path = || {
let mut path = mod_path.clone();
path.segments.push(name.clone());
path
};
for item in per_ns.iter_items() {
let path = mk_path();
match import_map.entry(item) {
Entry::Vacant(entry) => {
entry.insert(path);
}
Entry::Occupied(mut entry) => {
// If the new path is shorter, prefer that one.
if path.len() < entry.get().len() {
*entry.get_mut() = path;
} else {
continue;
}
}
}
// If we've just added a path to a module, descend into it. We might traverse
// modules multiple times, but only if the new path to it is shorter than the
// first (else we `continue` above).
if let Some(ModuleDefId::ModuleId(mod_id)) = item.as_module_def_id() {
worklist.push((mod_id, mk_path()));
}
}
}
}
Arc::new(Self { map: import_map })
}
/// Returns the `ModPath` needed to import/mention `item`, relative to this crate's root.
pub fn path_of(&self, item: ItemInNs) -> Option<&ModPath> {
self.map.get(&item)
}
}
impl fmt::Debug for ImportMap {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut importable_paths: Vec<_> = self
.map
.iter()
.map(|(item, modpath)| {
let ns = match item {
ItemInNs::Types(_) => "t",
ItemInNs::Values(_) => "v",
ItemInNs::Macros(_) => "m",
};
format!("- {} ({})", modpath, ns)
})
.collect();
importable_paths.sort();
f.write_str(&importable_paths.join("\n"))
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::test_db::TestDB;
use insta::assert_snapshot;
use ra_db::fixture::WithFixture;
use ra_db::SourceDatabase;
fn import_map(ra_fixture: &str) -> String {
let db = TestDB::with_files(ra_fixture);
let crate_graph = db.crate_graph();
let import_maps: Vec<_> = crate_graph
.iter()
.filter_map(|krate| {
let cdata = &crate_graph[krate];
let name = cdata.display_name.as_ref()?;
let map = db.import_map(krate);
Some(format!("{}:\n{:?}", name, map))
})
.collect();
import_maps.join("\n")
}
#[test]
fn smoke() {
let map = import_map(
r"
//- /main.rs crate:main deps:lib
mod private {
pub use lib::Pub;
pub struct InPrivateModule;
}
pub mod publ1 {
use lib::Pub;
}
pub mod real_pub {
pub use lib::Pub;
}
pub mod real_pu2 { // same path length as above
pub use lib::Pub;
}
//- /lib.rs crate:lib
pub struct Pub {}
pub struct Pub2; // t + v
struct Priv;
",
);
assert_snapshot!(map, @r###"
main:
- publ1 (t)
- real_pu2 (t)
- real_pub (t)
- real_pub::Pub (t)
lib:
- Pub (t)
- Pub2 (t)
- Pub2 (v)
"###);
}
#[test]
fn prefers_shortest_path() {
let map = import_map(
r"
//- /main.rs crate:main
pub mod sub {
pub mod subsub {
pub struct Def {}
}
pub use super::sub::subsub::Def;
}
",
);
assert_snapshot!(map, @r###"
main:
- sub (t)
- sub::Def (t)
- sub::subsub (t)
"###);
}
#[test]
fn type_reexport_cross_crate() {
// Reexports need to be visible from a crate, even if the original crate exports the item
// at a shorter path.
let map = import_map(
r"
//- /main.rs crate:main deps:lib
pub mod m {
pub use lib::S;
}
//- /lib.rs crate:lib
pub struct S;
",
);
assert_snapshot!(map, @r###"
main:
- m (t)
- m::S (t)
- m::S (v)
lib:
- S (t)
- S (v)
"###);
}
#[test]
fn macro_reexport() {
let map = import_map(
r"
//- /main.rs crate:main deps:lib
pub mod m {
pub use lib::pub_macro;
}
//- /lib.rs crate:lib
#[macro_export]
macro_rules! pub_macro {
() => {};
}
",
);
assert_snapshot!(map, @r###"
main:
- m (t)
- m::pub_macro (m)
lib:
- pub_macro (m)
"###);
}
#[test]
fn module_reexport() {
// Reexporting modules from a dependency adds all contents to the import map.
let map = import_map(
r"
//- /main.rs crate:main deps:lib
pub use lib::module as reexported_module;
//- /lib.rs crate:lib
pub mod module {
pub struct S;
}
",
);
assert_snapshot!(map, @r###"
main:
- reexported_module (t)
- reexported_module::S (t)
- reexported_module::S (v)
lib:
- module (t)
- module::S (t)
- module::S (v)
"###);
}
#[test]
fn cyclic_module_reexport() {
// A cyclic reexport does not hang.
let map = import_map(
r"
//- /lib.rs crate:lib
pub mod module {
pub struct S;
pub use super::sub::*;
}
pub mod sub {
pub use super::module;
}
",
);
assert_snapshot!(map, @r###"
lib:
- module (t)
- module::S (t)
- module::S (v)
- sub (t)
"###);
}
#[test]
fn private_macro() {
let map = import_map(
r"
//- /lib.rs crate:lib
macro_rules! private_macro {
() => {};
}
",
);
assert_snapshot!(map, @r###"
lib:
"###);
}
}