revamp for memory safety

1 files changed, 34 insertions, 0 deletions

diff --git a/src/ctxt.rs b/src/ctxt.rs
new file mode 100644
index 0000000..7cd8a74
--- /dev/null
+++ b/src/ctxt.rs
@@ -0,0 +1,34 @@
+//! Execution context
+
+use core::marker::PhantomData;
+use core::cell::UnsafeCell;
+
+/// Data local to an execution context
+pub struct Local<T, Ctxt>
+    where Ctxt: Token
+{
+    _ctxt: PhantomData<Ctxt>,
+    data: UnsafeCell<T>,
+}
+
+impl<T, Ctxt> Local<T, Ctxt>
+    where Ctxt: Token
+{
+    /// Initializes the local data
+    pub const fn new(value: T) -> Self {
+        Local {
+            _ctxt: PhantomData,
+            data: UnsafeCell::new(value),
+        }
+    }
+
+    /// Acquires a reference to the local data
+    pub fn borrow<'a>(&'static self, _ctxt: &'a Ctxt) -> &'a T {
+        unsafe { &*self.data.get() }
+    }
+}
+
+unsafe impl<T, Ctxt> Sync for Local<T, Ctxt> where Ctxt: Token {}
+
+/// A unique token that identifies an execution context
+pub unsafe trait Token {}