Asyncify font loading 🪐

2 files changed, 18 insertions, 4 deletions

diff --git a/src/func/macros.rs b/src/func/macros.rs
index 2da219bc..a89156b7 100644
--- a/src/func/macros.rs
+++ b/src/func/macros.rs
@@ -108,9 +108,20 @@ macro_rules! function {
 
     // (2-arg) Parse a layout-definition with all arguments.
     (@layout $type:ident | layout($this:ident, $ctx:pat) $code:block) => {
-        impl $crate::func::LayoutFunc for $type {
-            fn layout(&$this, $ctx: LayoutContext) -> LayoutResult<Commands> {
-                Ok($code)
+        impl LayoutFunc for $type {
+            fn layout<'a, 'life0, 'life1, 'async_trait>(
+                &'a $this,
+                $ctx: LayoutContext<'life0, 'life1>
+            ) -> std::pin::Pin<Box<
+                dyn std::future::Future<Output = LayoutResult<Commands<'a>>> + 'async_trait
+            >>
+            where
+                'a: 'async_trait,
+                'life0: 'async_trait,
+                'life1: 'async_trait,
+                Self: 'async_trait,
+            {
+                Box::pin(async move { Ok($code) })
             }
         }
     };
diff --git a/src/func/mod.rs b/src/func/mod.rs
index 427e5b6f..a0875cf9 100644
--- a/src/func/mod.rs
+++ b/src/func/mod.rs
@@ -4,6 +4,7 @@ use std::any::Any;
 use std::collections::HashMap;
 use std::fmt::{self, Debug, Formatter};
 
+use async_trait::async_trait;
 use self::prelude::*;
 
 #[macro_use]
@@ -24,6 +25,7 @@ pub mod prelude {
     pub use Command::*;
 }
 
+
 /// Types representing functions that are parsed from source code.
 pub trait ParseFunc {
     type Meta: Clone;
@@ -43,12 +45,13 @@ pub trait ParseFunc {
 /// The trait `[LayoutFuncBounds]` is automatically implemented for types which
 /// can be used as functions, that is, all types which fulfill the bounds `Debug
 /// + PartialEq + 'static`.
+#[async_trait(?Send)]
 pub trait LayoutFunc: LayoutFuncBounds {
     /// Layout this function in a given context.
     ///
     /// Returns a sequence of layouting commands which describe what the
     /// function is doing.
-    fn layout(&self, ctx: LayoutContext) -> LayoutResult<Commands>;
+    async fn layout<'a>(&'a self, ctx: LayoutContext<'_, '_>) -> LayoutResult<Commands<'a>>;
 }
 
 impl dyn LayoutFunc {