refactor(tvix/store): use composition in tvix_store crate

Change-Id: Ie6290b296baba2b987f1a61c9bb4c78549ac11f1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11983
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: yuka <yuka@yuka.dev>
Tested-by: BuildkiteCI

tvix/store/src/pathinfoservice/memory.rs

@@ -7,6 +7,7 @@ use std::{collections::HashMap, sync::Arc};
 use tokio::sync::RwLock;
 use tonic::async_trait;
 use tracing::instrument;
+use tvix_castore::composition::{CompositionContext, ServiceBuilder};
 use tvix_castore::Error;
 
 #[derive(Default)]
@@ -59,3 +60,30 @@ impl PathInfoService for MemoryPathInfoService {
         })
     }
 }
+
+#[derive(serde::Deserialize, Debug)]
+#[serde(deny_unknown_fields)]
+pub struct MemoryPathInfoServiceConfig {}
+
+impl TryFrom<url::Url> for MemoryPathInfoServiceConfig {
+    type Error = Box<dyn std::error::Error + Send + Sync>;
+    fn try_from(url: url::Url) -> Result<Self, Self::Error> {
+        // memory doesn't support host or path in the URL.
+        if url.has_host() || !url.path().is_empty() {
+            return Err(Error::StorageError("invalid url".to_string()).into());
+        }
+        Ok(MemoryPathInfoServiceConfig {})
+    }
+}
+
+#[async_trait]
+impl ServiceBuilder for MemoryPathInfoServiceConfig {
+    type Output = dyn PathInfoService;
+    async fn build<'a>(
+        &'a self,
+        _instance_name: &str,
+        _context: &CompositionContext,
+    ) -> Result<Arc<dyn PathInfoService>, Box<dyn std::error::Error + Send + Sync + 'static>> {
+        Ok(Arc::new(MemoryPathInfoService::default()))
+    }
+}