1 files changed, 42 insertions, 0 deletions

diff --git a/src/yellow/mod.rs b/src/yellow/mod.rs
new file mode 100644
index 000000000..236328a7f
--- /dev/null
+++ b/src/yellow/mod.rs
@@ -0,0 +1,42 @@
+mod green;
+mod red;
+mod syntax;
+
+use std::{
+    sync::{Arc, Weak},
+    ops::Deref,
+    mem
+};
+pub(crate) use self::{
+    green::{GreenNode, TextLen},
+    red::RedNode,
+    syntax::SError,
+};
+pub use self::syntax::SyntaxNode;
+
+// This could be just `*const T`, but we use `Weak` for additional checks
+#[derive(Debug)]
+pub(crate) struct Ptr<T>(Weak<T>);
+
+impl<T> Clone for Ptr<T> {
+    fn clone(&self) -> Self {
+        Ptr(self.0.clone())
+    }
+}
+
+impl<T> Ptr<T> {
+    fn clone(self_: &Ptr<T>) -> Ptr<T> {
+        Ptr(Weak::clone(&self_.0))
+    }
+
+    fn new(arc: &Arc<T>) -> Ptr<T> {
+        Ptr(Arc::downgrade(arc))
+    }
+
+    unsafe fn get(&self) -> &T {
+        let t = self.0.upgrade()
+            .expect("caller must guarantee that Ptr is not null");
+        let t: &T = &*t;
+        mem::transmute(t)
+    }
+}