refactor(tvix/castore/directory): borrow in SimplePutter

This means we don't need to clone self in all implementations using
SimplePutter.

Change-Id: I11347028801c43c5cc9920c0a9edf47627096bce
Reviewed-on: https://cl.tvl.fyi/c/depot/+/13262
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: edef <edef@edef.eu>
Tested-by: BuildkiteCI

tvix/castore/src/directoryservice/bigtable.rs

@@ -319,11 +319,8 @@ impl DirectoryService for BigtableDirectoryService {
     }
 
     #[instrument(skip_all, fields(instance_name=%self.instance_name))]
-    fn put_multiple_start(&self) -> Box<(dyn DirectoryPutter + 'static)>
-    where
-        Self: Clone,
-    {
-        Box::new(SimplePutter::new(self.clone()))
+    fn put_multiple_start(&self) -> Box<(dyn DirectoryPutter + '_)> {
+        Box::new(SimplePutter::new(self))
     }
 }
 

tvix/castore/src/directoryservice/combinators.rs

@@ -20,7 +20,6 @@ use crate::Error;
 /// which is useful when far does not support accessing intermediate directories (but near does).
 /// There is no negative cache.
 /// Inserts and listings are not implemented for now.
-#[derive(Clone)]
 pub struct Cache<DS1, DS2> {
     instance_name: String,
     near: DS1,
@@ -143,8 +142,8 @@ where
     }
 
     #[instrument(skip_all)]
-    fn put_multiple_start(&self) -> Box<(dyn DirectoryPutter + 'static)> {
-        Box::new(SimplePutter::new((*self).clone()))
+    fn put_multiple_start(&self) -> Box<(dyn DirectoryPutter + '_)> {
+        Box::new(SimplePutter::new(self))
     }
 }
 

tvix/castore/src/directoryservice/memory.rs

@@ -66,11 +66,8 @@ impl DirectoryService for MemoryDirectoryService {
     }
 
     #[instrument(skip_all, fields(instance_name=%self.instance_name))]
-    fn put_multiple_start(&self) -> Box<(dyn DirectoryPutter + 'static)>
-    where
-        Self: Clone,
-    {
-        Box::new(SimplePutter::new(self.clone()))
+    fn put_multiple_start(&self) -> Box<(dyn DirectoryPutter + '_)> {
+        Box::new(SimplePutter::new(self))
     }
 }
 

tvix/castore/src/directoryservice/simple_putter.rs

@@ -10,14 +10,17 @@ use tracing::warn;
 /// This is an implementation of DirectoryPutter that simply
 /// inserts individual Directory messages one by one, on close, after
 /// they successfully validated.
-pub struct SimplePutter<DS: DirectoryService> {
-    directory_service: DS,
+pub struct SimplePutter<'a, DS> {
+    directory_service: &'a DS,
 
     directory_validator: Option<DirectoryGraph<LeavesToRootValidator>>,
 }
 
-impl<DS: DirectoryService> SimplePutter<DS> {
-    pub fn new(directory_service: DS) -> Self {
+impl<'a, DS> SimplePutter<'a, DS>
+where
+    DS: DirectoryService,
+{
+    pub fn new(directory_service: &'a DS) -> Self {
         Self {
             directory_service,
             directory_validator: Some(Default::default()),
@@ -26,7 +29,7 @@ impl<DS: DirectoryService> SimplePutter<DS> {
 }
 
 #[async_trait]
-impl<DS: DirectoryService + 'static> DirectoryPutter for SimplePutter<DS> {
+impl<DS: DirectoryService + 'static> DirectoryPutter for SimplePutter<'_, DS> {
     #[instrument(level = "trace", skip_all, fields(directory.digest=%directory.digest()), err)]
     async fn put(&mut self, directory: Directory) -> Result<(), Error> {
         match self.directory_validator {