move db basics to ra_db

This should allow to move hir to a separate crate

crates/ra_db/src/lib.rs

@@ -0,0 +1,69 @@
+//! ra_db defines basic database traits. Concrete DB is defined by ra_analysis.
+
+extern crate ra_editor;
+extern crate ra_syntax;
+extern crate relative_path;
+extern crate rustc_hash;
+extern crate salsa;
+
+mod syntax_ptr;
+mod file_resolver;
+mod input;
+mod loc2id;
+
+use std::sync::Arc;
+use ra_editor::LineIndex;
+use ra_syntax::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},
+};
+
+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))
+}