move db basics to ra_db

This should allow to move hir to a separate crate

crates/ra_analysis/src/syntax_ptr.rs

@@ -1,48 +0,0 @@
-use ra_syntax::{SourceFileNode, SyntaxKind, SyntaxNode, SyntaxNodeRef, TextRange};
-
-/// A pionter to a syntax node inside a file.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(crate) struct LocalSyntaxPtr {
-    range: TextRange,
-    kind: SyntaxKind,
-}
-
-impl LocalSyntaxPtr {
-    pub(crate) fn new(node: SyntaxNodeRef) -> LocalSyntaxPtr {
-        LocalSyntaxPtr {
-            range: node.range(),
-            kind: node.kind(),
-        }
-    }
-
-    pub(crate) fn resolve(self, file: &SourceFileNode) -> SyntaxNode {
-        let mut curr = file.syntax();
-        loop {
-            if curr.range() == self.range && curr.kind() == self.kind {
-                return curr.owned();
-            }
-            curr = curr
-                .children()
-                .find(|it| self.range.is_subrange(&it.range()))
-                .unwrap_or_else(|| panic!("can't resolve local ptr to SyntaxNode: {:?}", self))
-        }
-    }
-
-    pub(crate) fn range(self) -> TextRange {
-        self.range
-    }
-}
-
-#[test]
-fn test_local_syntax_ptr() {
-    use ra_syntax::{ast, AstNode};
-    let file = SourceFileNode::parse("struct Foo { f: u32, }");
-    let field = file
-        .syntax()
-        .descendants()
-        .find_map(ast::NamedFieldDef::cast)
-        .unwrap();
-    let ptr = LocalSyntaxPtr::new(field.syntax());
-    let field_syntax = ptr.resolve(&file);
-    assert_eq!(field.syntax(), field_syntax);
-}