Merge remote-tracking branch 'upstream/master' into 503-hover-doc-links

1 files changed, 167 insertions, 0 deletions

diff --git a/crates/base_db/src/lib.rs b/crates/base_db/src/lib.rs
new file mode 100644
index 000000000..ee3415850
--- /dev/null
+++ b/crates/base_db/src/lib.rs
@@ -0,0 +1,167 @@
+//! base_db defines basic database traits. The concrete DB is defined by ide.
+mod cancellation;
+mod input;
+pub mod fixture;
+
+use std::{panic, sync::Arc};
+
+use rustc_hash::FxHashSet;
+use syntax::{ast, Parse, SourceFile, TextRange, TextSize};
+
+pub use crate::{
+    cancellation::Canceled,
+    input::{
+        CrateData, CrateGraph, CrateId, CrateName, Dependency, Edition, Env, FileId, ProcMacroId,
+        SourceRoot, SourceRootId,
+    },
+};
+pub use salsa;
+pub use vfs::{file_set::FileSet, VfsPath};
+
+#[macro_export]
+macro_rules! impl_intern_key {
+    ($name:ident) => {
+        impl $crate::salsa::InternKey for $name {
+            fn from_intern_id(v: $crate::salsa::InternId) -> Self {
+                $name(v)
+            }
+            fn as_intern_id(&self) -> $crate::salsa::InternId {
+                self.0
+            }
+        }
+    };
+}
+
+pub trait Upcast<T: ?Sized> {
+    fn upcast(&self) -> &T;
+}
+
+pub trait CheckCanceled {
+    /// Aborts current query if there are pending changes.
+    ///
+    /// rust-analyzer needs to be able to answer semantic questions about the
+    /// code while the code is being modified. A common problem is that a
+    /// long-running query is being calculated when a new change arrives.
+    ///
+    /// We can't just apply the change immediately: this will cause the pending
+    /// query to see inconsistent state (it will observe an absence of
+    /// repeatable read). So what we do is we **cancel** all pending queries
+    /// before applying the change.
+    ///
+    /// We implement cancellation by panicking with a special value and catching
+    /// it on the API boundary. Salsa explicitly supports this use-case.
+    fn check_canceled(&self);
+
+    fn catch_canceled<F, T>(&self, f: F) -> Result<T, Canceled>
+    where
+        Self: Sized + panic::RefUnwindSafe,
+        F: FnOnce(&Self) -> T + panic::UnwindSafe,
+    {
+        panic::catch_unwind(|| f(self)).map_err(|err| match err.downcast::<Canceled>() {
+            Ok(canceled) => *canceled,
+            Err(payload) => panic::resume_unwind(payload),
+        })
+    }
+}
+
+impl<T: salsa::Database> CheckCanceled for T {
+    fn check_canceled(&self) {
+        if self.salsa_runtime().is_current_revision_canceled() {
+            Canceled::throw()
+        }
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+pub struct FilePosition {
+    pub file_id: FileId,
+    pub offset: TextSize,
+}
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct FileRange {
+    pub file_id: FileId,
+    pub range: TextRange,
+}
+
+pub const DEFAULT_LRU_CAP: usize = 128;
+
+pub trait FileLoader {
+    /// Text of the file.
+    fn file_text(&self, file_id: FileId) -> Arc<String>;
+    /// Note that we intentionally accept a `&str` and not a `&Path` here. This
+    /// method exists to handle `#[path = "/some/path.rs"] mod foo;` and such,
+    /// so the input is guaranteed to be utf-8 string. One might be tempted to
+    /// introduce some kind of "utf-8 path with / separators", but that's a bad idea. Behold
+    /// `#[path = "C://no/way"]`
+    fn resolve_path(&self, anchor: FileId, path: &str) -> Option<FileId>;
+    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>>;
+}
+
+/// Database which stores all significant input facts: source code and project
+/// model. Everything else in rust-analyzer is derived from these queries.
+#[salsa::query_group(SourceDatabaseStorage)]
+pub trait SourceDatabase: CheckCanceled + FileLoader + std::fmt::Debug {
+    // Parses the file into the syntax tree.
+    #[salsa::invoke(parse_query)]
+    fn parse(&self, file_id: FileId) -> Parse<ast::SourceFile>;
+
+    /// The crate graph.
+    #[salsa::input]
+    fn crate_graph(&self) -> Arc<CrateGraph>;
+}
+
+fn parse_query(db: &dyn SourceDatabase, file_id: FileId) -> Parse<ast::SourceFile> {
+    let _p = profile::span("parse_query").detail(|| format!("{:?}", file_id));
+    let text = db.file_text(file_id);
+    SourceFile::parse(&*text)
+}
+
+/// We don't want to give HIR knowledge of source roots, hence we extract these
+/// methods into a separate DB.
+#[salsa::query_group(SourceDatabaseExtStorage)]
+pub trait SourceDatabaseExt: SourceDatabase {
+    #[salsa::input]
+    fn file_text(&self, file_id: FileId) -> Arc<String>;
+    /// Path to a file, relative to the root of its source root.
+    /// Source root of the file.
+    #[salsa::input]
+    fn file_source_root(&self, file_id: FileId) -> SourceRootId;
+    /// Contents of the source root.
+    #[salsa::input]
+    fn source_root(&self, id: SourceRootId) -> Arc<SourceRoot>;
+
+    fn source_root_crates(&self, id: SourceRootId) -> Arc<FxHashSet<CrateId>>;
+}
+
+fn source_root_crates(db: &dyn SourceDatabaseExt, id: SourceRootId) -> Arc<FxHashSet<CrateId>> {
+    let graph = db.crate_graph();
+    let res = graph
+        .iter()
+        .filter(|&krate| {
+            let root_file = graph[krate].root_file_id;
+            db.file_source_root(root_file) == id
+        })
+        .collect::<FxHashSet<_>>();
+    Arc::new(res)
+}
+
+/// Silly workaround for cyclic deps between the traits
+pub struct FileLoaderDelegate<T>(pub T);
+
+impl<T: SourceDatabaseExt> FileLoader for FileLoaderDelegate<&'_ T> {
+    fn file_text(&self, file_id: FileId) -> Arc<String> {
+        SourceDatabaseExt::file_text(self.0, file_id)
+    }
+    fn resolve_path(&self, anchor: FileId, path: &str) -> Option<FileId> {
+        // FIXME: this *somehow* should be platform agnostic...
+        let source_root = self.0.file_source_root(anchor);
+        let source_root = self.0.source_root(source_root);
+        source_root.file_set.resolve_path(anchor, path)
+    }
+
+    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>> {
+        let source_root = self.0.file_source_root(file_id);
+        self.0.source_root_crates(source_root)
+    }
+}