Start implementing generic wrapper types

rustler/src/types/mod.rs

@@ -1,5 +1,9 @@
 use crate::{Env, Error, NifResult, Term};
 
+#[macro_use]
+mod wrapper;
+pub(crate) use self::wrapper::wrapper;
+
 #[macro_use]
 pub mod atom;
 pub use crate::types::atom::Atom;

rustler/src/types/reference.rs

@@ -1,22 +1,24 @@
 use std::ops::Deref;
 
-use crate::{Decoder, Encoder, Env, Error, NifResult, Term};
+use crate::{Decoder, Encoder, Env, Error, NifResult, Term, TermType};
 
 use crate::sys::enif_make_ref;
 
-/// Wrapper for BEAM reference terms.
-#[derive(PartialEq, Eq, Clone, Copy)]
-pub struct Reference<'a>(Term<'a>);
+wrapper!(Reference, TermType::Ref);
 
-impl Reference<'_> {
-    /// Returns a representation of self in the given Env.
-    ///
-    /// If the term is already is in the provided env, it will be directly returned. Otherwise
-    /// the term will be copied over.
-    pub fn in_env<'b>(&self, env: Env<'b>) -> Reference<'b> {
-        Reference(self.0.in_env(env))
-    }
-}
+/// Wrapper for BEAM reference terms.
+// #[derive(PartialEq, Eq, Clone, Copy)]
+// pub struct Reference<'a>(Term<'a>);
+//
+// impl<'a> Reference<'a> {
+//     /// Returns a representation of self in the given Env.
+//     ///
+//     /// If the term is already is in the provided env, it will be directly returned. Otherwise
+//     /// the term will be copied over.
+//     pub fn in_env<'b>(&self, env: Env<'b>) -> Reference<'b> {
+//         Reference(self.0.in_env(env))
+//     }
+// }
 
 impl<'a> Deref for Reference<'a> {
     type Target = Term<'a>;

rustler/src/types/wrapper.rs

@@ -0,0 +1,50 @@
+use crate::TermType;
+
+struct WrapperError;
+
+pub trait Wrapper<'a>: Sized {
+    const WRAPPED_TYPE: TermType;
+
+    fn wrap<'b>(term: Term<'a>) -> Result<Self, WrapperError> {
+        if term.get_type() == Self::WRAPPED_TYPE {
+            unsafe { Ok(Self::wrap_unsafe(term)) }
+        } else {
+            Err(WrapperError)
+        }
+    }
+
+    fn unwrap(&self) -> Term<'a>;
+
+    unsafe fn wrap_unsafe(term: Term<'a>) -> Self;
+
+    /// Returns a representation of self in the given Env.
+    ///
+    /// If the term is already is in the provided env, it will be directly returned. Otherwise
+    /// the term will be copied over.
+    fn in_env<'b>(&self, env: Env<'b>) -> impl Wrapper<'b, WRAPPED_TYPE = Self::WrappedType> {
+        self.unwrap().in_env(env)
+    }
+}
+
+macro_rules! wrapper {
+    ($name:ident, $term_type:path) => {
+        #[derive(PartialEq, Eq, Clone, Copy)]
+        pub struct $name<'a>(Term<'a>);
+
+        impl<'a> $crate::types::wrapper::Wrapper<'a> for $name<'a> {
+            const WrappedType: TermType = $term_type;
+
+            unsafe fn wrap_unsafe(term: Term<'a>) -> Self {
+                $name(term)
+            }
+
+            fn unwrap(&self) -> Term<'a> {
+                self.0
+            }
+        }
+    };
+}
+
+pub(crate) use wrapper;
+
+use crate::{Env, Term};