From 0787d001e36b4b61208c5e18bcc56b210b9ef5bc Mon Sep 17 00:00:00 2001
From: Lachlan Sneff <lachlan.sneff@gmail.com>
Date: Thu, 28 Mar 2019 11:41:14 -0700
Subject: [PATCH] Add data support to import macro

---
 lib/runtime-core/src/import.rs | 14 ++++++++++++++
 lib/runtime-core/src/macros.rs | 22 ++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/lib/runtime-core/src/import.rs b/lib/runtime-core/src/import.rs
index 4c8401f06..32b089462 100644
--- a/lib/runtime-core/src/import.rs
+++ b/lib/runtime-core/src/import.rs
@@ -4,6 +4,7 @@ use std::collections::VecDeque;
 use std::{
     cell::{Ref, RefCell},
     rc::Rc,
+    ffi::c_void,
 };
 
 pub trait LikeNamespace {
@@ -45,6 +46,7 @@ impl IsExport for Export {
 /// ```
 pub struct ImportObject {
     map: Rc<RefCell<HashMap<String, Box<dyn LikeNamespace>>>>,
+    state_creator: Option<Rc<Fn() -> (*mut c_void, fn(*mut c_void))>>,
 }
 
 impl ImportObject {
@@ -52,6 +54,17 @@ impl ImportObject {
     pub fn new() -> Self {
         Self {
             map: Rc::new(RefCell::new(HashMap::new())),
+            state_creator: None,
+        }
+    }
+
+    pub fn new_with_data<F>(state_creator: F) -> Self 
+    where
+        F: Fn() -> (*mut c_void, fn(*mut c_void)) + 'static,
+    {
+        Self {
+            map: Rc::new(RefCell::new(HashMap::new())),
+            state_creator: Some(Rc::new(state_creator)),
         }
     }
 
@@ -98,6 +111,7 @@ impl ImportObject {
     pub fn clone_ref(&self) -> Self {
         Self {
             map: Rc::clone(&self.map),
+            state_creator: self.state_creator.clone(),
         }
     }
 
diff --git a/lib/runtime-core/src/macros.rs b/lib/runtime-core/src/macros.rs
index e23ce1185..6c608fc92 100644
--- a/lib/runtime-core/src/macros.rs
+++ b/lib/runtime-core/src/macros.rs
@@ -37,6 +37,13 @@ macro_rules! func {
 ///         "foo" => func!(foo),
 ///     },
 /// };
+/// 
+/// let imports_with_state = imports! {
+///     || (0 as _, |_a| {}),
+///     "env" => {
+///         "foo" => func!(foo),
+///     },
+/// };
 ///
 /// fn foo(_: &mut Ctx, n: i32) -> i32 {
 ///     n
@@ -57,6 +64,21 @@ macro_rules! imports {
             import_object.register($ns_name, ns);
         })*
 
+        import_object
+    }};
+    ($state_gen:expr, $( $ns_name:expr => $ns:tt, )* ) => {{
+        use $crate::{
+            import::{ImportObject, Namespace},
+        };
+
+        let mut import_object = ImportObject::new_with_data($state_gen);
+
+        $({
+            let ns = $crate::__imports_internal!($ns);
+
+            import_object.register($ns_name, ns);
+        })*
+
         import_object
     }};
 }