Copy spin-core and spin-app crates from prototype

Signed-off-by: Lann Martin <lann.martin@fermyon.com>

Author: lann

Cargo.lock

@@ -69,8 +69,10 @@ e2e-tests = []
 
 [workspace]
 members = [
+    "crates/app",
     "crates/build",
     "crates/config",
+    "crates/core",
     "crates/engine",
     "crates/http",
     "crates/loader",

Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "spin-app"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "1.0"
+async-trait = "0.1"
+ouroboros = "0.15"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+spin-core = { path = "../core" }
+thiserror = "1.0"

crates/app/Cargo.toml

@@ -0,0 +1,51 @@
+use std::sync::Arc;
+
+use spin_core::{EngineBuilder, HostComponent, HostComponentsData};
+
+use crate::AppComponent;
+
+pub trait DynamicHostComponent: HostComponent {
+    fn update_data(&self, data: &mut Self::Data, component: &AppComponent) -> anyhow::Result<()>;
+}
+
+impl<DHC: DynamicHostComponent> DynamicHostComponent for Arc<DHC> {
+    fn update_data(&self, data: &mut Self::Data, component: &AppComponent) -> anyhow::Result<()> {
+        (**self).update_data(data, component)
+    }
+}
+
+type DataUpdater =
+    Box<dyn Fn(&mut HostComponentsData, &AppComponent) -> anyhow::Result<()> + Send + Sync>;
+
+#[derive(Default)]
+pub struct DynamicHostComponents {
+    data_updaters: Vec<DataUpdater>,
+}
+
+impl DynamicHostComponents {
+    pub fn add_dynamic_host_component<T: Send + Sync, DHC: DynamicHostComponent>(
+        &mut self,
+        engine_builder: &mut EngineBuilder<T>,
+        host_component: DHC,
+    ) -> anyhow::Result<()> {
+        let host_component = Arc::new(host_component);
+        let handle = engine_builder.add_host_component(host_component.clone())?;
+        self.data_updaters
+            .push(Box::new(move |host_components_data, component| {
+                let data = host_components_data.get_or_insert(handle);
+                host_component.update_data(data, component)
+            }));
+        Ok(())
+    }
+
+    pub fn update_data(
+        &self,
+        host_components_data: &mut HostComponentsData,
+        component: &AppComponent,
+    ) -> anyhow::Result<()> {
+        for data_updater in &self.data_updaters {
+            data_updater(host_components_data, component)?;
+        }
+        Ok(())
+    }
+}