add a new fetch_single_local_direct method

Summary: add a new fetch_single_local_direct method

Reviewed By: quark-zju

Differential Revision: D72165005

fbshipit-source-id: 61e9f51f57267ee25f53da0805880e546b221000

Author: Liubov Dmitrieva

eden/scm/lib/cas-client/re-cas-common/src/lib.rs

@@ -89,6 +89,13 @@ macro_rules! re_client {
 
         #[$crate::async_trait]
         impl $crate::CasClient for $struct {
+            fn fetch_single_local_direct(
+                &self,
+                _fctx: $crate::FetchContext,
+                digest: &$crate::CasDigest,
+            ) -> Result<Option<ScmBlob>> {
+                return Ok(None);
+            }
             async fn fetch<'a>(
                 &'a self,
                 _fctx: $crate::FetchContext,

eden/scm/lib/cas-client/src/lib.rs

@@ -120,6 +120,12 @@ pub fn new(config: Arc<dyn Config>) -> anyhow::Result<Option<Arc<dyn CasClient>>
 #[async_trait::async_trait]
 #[auto_impl::auto_impl(&, Box, Arc)]
 pub trait CasClient: Sync + Send {
+    /// Fetch a single blob from local CAS caches.
+    fn fetch_single_local_direct(
+        &self,
+        _fctx: FetchContext,
+        digest: &CasDigest,
+    ) -> anyhow::Result<Option<ScmBlob>>;
     /// Fetch blobs from CAS.
     async fn fetch<'a>(
         &'a self,

eden/scm/lib/eagerepo/src/trait_impls.rs

@@ -182,6 +182,16 @@ impl ReadRootTreeIds for EagerRepoStore {
 
 #[async_trait::async_trait]
 impl CasClient for EagerRepoStore {
+    /// Fetch a single blob from local CAS caches.
+    fn fetch_single_local_direct(
+        &self,
+        _fctx: FetchContext,
+        digest: &CasDigest,
+    ) -> anyhow::Result<Option<ScmBlob>> {
+        self.get_cas_blob(*digest)
+            .map_err(Into::into)
+            .map(|data| data.map(ScmBlob::Bytes))
+    }
     async fn fetch<'a>(
         &'a self,
         _fctx: FetchContext,