Merge remote-tracking branch 'origin/master' into feat/multi-window-support

# Conflicts:
#	Cargo.toml
#	core/src/window/icon.rs
#	core/src/window/id.rs
#	core/src/window/position.rs
#	core/src/window/settings.rs
#	examples/integration/src/main.rs
#	examples/integration_opengl/src/main.rs
#	glutin/src/application.rs
#	native/src/subscription.rs
#	native/src/window.rs
#	runtime/src/window/action.rs
#	src/lib.rs
#	src/window.rs
#	winit/Cargo.toml
#	winit/src/application.rs
#	winit/src/icon.rs
#	winit/src/settings.rs
#	winit/src/window.rs

1 files changed, 39 insertions, 0 deletions

diff --git a/runtime/src/system/action.rs b/runtime/src/system/action.rs
new file mode 100644
index 00000000..dea9536f
--- /dev/null
+++ b/runtime/src/system/action.rs
@@ -0,0 +1,39 @@
+use crate::system;
+
+use iced_futures::MaybeSend;
+use std::fmt;
+
+/// An operation to be performed on the system.
+pub enum Action<T> {
+    /// Query system information and produce `T` with the result.
+    QueryInformation(Box<dyn Closure<T>>),
+}
+
+pub trait Closure<T>: Fn(system::Information) -> T + MaybeSend {}
+
+impl<T, O> Closure<O> for T where T: Fn(system::Information) -> O + MaybeSend {}
+
+impl<T> Action<T> {
+    /// Maps the output of a system [`Action`] using the provided closure.
+    pub fn map<A>(
+        self,
+        f: impl Fn(T) -> A + 'static + MaybeSend + Sync,
+    ) -> Action<A>
+    where
+        T: 'static,
+    {
+        match self {
+            Self::QueryInformation(o) => {
+                Action::QueryInformation(Box::new(move |s| f(o(s))))
+            }
+        }
+    }
+}
+
+impl<T> fmt::Debug for Action<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::QueryInformation(_) => write!(f, "Action::QueryInformation"),
+        }
+    }
+}