Draft iced_devtools subcrate structure

devtools/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "iced_devtools"
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+homepage.workspace = true
+categories.workspace = true
+keywords.workspace = true
+rust-version.workspace = true
+
+[lints]
+workspace = true
+
+[dependencies]
+iced_program.workspace = true
+iced_widget.workspace = true

devtools/src/lib.rs

@@ -0,0 +1,161 @@
+#![allow(missing_docs)]
+use crate::runtime::futures;
+use iced_program as program;
+use iced_widget::core;
+use iced_widget::runtime;
+
+use crate::core::Element;
+use crate::core::theme;
+use crate::core::window;
+use crate::futures::Subscription;
+use crate::program::Program;
+use crate::runtime::Task;
+
+use std::fmt;
+
+pub fn attach(program: impl Program + 'static) -> impl Program {
+    struct Attach<P> {
+        program: P,
+    }
+
+    impl<P> Program for Attach<P>
+    where
+        P: Program + 'static,
+    {
+        type State = DevTools<P>;
+        type Message = Message<P>;
+        type Theme = P::Theme;
+        type Renderer = P::Renderer;
+        type Executor = P::Executor;
+
+        fn name() -> &'static str {
+            P::name()
+        }
+
+        fn boot(&self) -> (Self::State, Task<Self::Message>) {
+            let (state, task) = self.program.boot();
+
+            (DevTools { state }, task.map(Message::Program))
+        }
+
+        fn update(
+            &self,
+            state: &mut Self::State,
+            message: Self::Message,
+        ) -> Task<Self::Message> {
+            state.update(&self.program, message)
+        }
+
+        fn view<'a>(
+            &self,
+            state: &'a Self::State,
+            window: window::Id,
+        ) -> Element<'a, Self::Message, Self::Theme, Self::Renderer> {
+            state.view(&self.program, window)
+        }
+
+        fn title(&self, state: &Self::State, window: window::Id) -> String {
+            state.title(&self.program, window)
+        }
+
+        fn subscription(
+            &self,
+            state: &Self::State,
+        ) -> runtime::futures::Subscription<Self::Message> {
+            state.subscription(&self.program)
+        }
+
+        fn theme(
+            &self,
+            state: &Self::State,
+            window: window::Id,
+        ) -> Self::Theme {
+            state.theme(&self.program, window)
+        }
+
+        fn style(
+            &self,
+            state: &Self::State,
+            theme: &Self::Theme,
+        ) -> theme::Style {
+            state.style(&self.program, theme)
+        }
+
+        fn scale_factor(&self, state: &Self::State, window: window::Id) -> f64 {
+            state.scale_factor(&self.program, window)
+        }
+    }
+
+    Attach { program }
+}
+
+struct DevTools<P>
+where
+    P: Program,
+{
+    state: P::State,
+}
+
+impl<P> DevTools<P>
+where
+    P: Program + 'static,
+{
+    pub fn title(&self, program: &P, window: window::Id) -> String {
+        program.title(&self.state, window)
+    }
+
+    pub fn update(
+        &mut self,
+        program: &P,
+        message: Message<P>,
+    ) -> Task<Message<P>> {
+        match message {
+            Message::Program(message) => program
+                .update(&mut self.state, message)
+                .map(Message::Program),
+        }
+    }
+
+    pub fn view(
+        &self,
+        program: &P,
+        window: window::Id,
+    ) -> Element<'_, Message<P>, P::Theme, P::Renderer> {
+        program.view(&self.state, window).map(Message::Program)
+    }
+
+    pub fn subscription(&self, program: &P) -> Subscription<Message<P>> {
+        program.subscription(&self.state).map(Message::Program)
+    }
+
+    pub fn theme(&self, program: &P, window: window::Id) -> P::Theme {
+        program.theme(&self.state, window)
+    }
+
+    pub fn style(&self, program: &P, theme: &P::Theme) -> theme::Style {
+        program.style(&self.state, theme)
+    }
+
+    pub fn scale_factor(&self, program: &P, window: window::Id) -> f64 {
+        program.scale_factor(&self.state, window)
+    }
+}
+
+#[derive(Clone)]
+enum Message<P>
+where
+    P: Program,
+{
+    Program(P::Message),
+}
+
+impl<P> fmt::Debug for Message<P>
+where
+    P: Program,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Message::Program(message) => message.fmt(f),
+        }
+    }
+}