treemanifest: flush shared stores when flushing local stores

Summary:
The Rust contentstore has no way to flush the shared stores, except
when the object is destructed. In treemanifest, the lifetime of the shared store
seems to be different from with files and we're not seeing them flushes
appropriately during certain commands. Let's make the flush api also flush the
shared stores.

Reviewed By: quark-zju

Differential Revision: D23662976

fbshipit-source-id: a542c3e45d5b489fcb5faf2726854cb49df16f4c

eden/scm/edenscm/hgext/remotefilelog/contentstore.py

@@ -165,6 +165,11 @@ class unioncontentstore(object):
                 store.prefetch(keys)
                 break
 
+    def flush(self):
+        for store in self.stores:
+            if util.safehasattr(store, "flush"):
+                store.flush()
+
 
 class manifestrevlogstore(object):
     def __init__(self, repo):

eden/scm/edenscm/hgext/remotefilelog/metadatastore.py

@@ -48,3 +48,8 @@ class unionmetadatastore(object):
 
     def removestore(self, store):
         self.stores.remove(store)
+
+    def flush(self):
+        for store in self.stores:
+            if util.safehasattr(store, "flush"):
+                store.flush()

eden/scm/lib/revisionstore/src/contentstore.rs

@@ -186,6 +186,7 @@ impl HgIdMutableDeltaStore for ContentStore {
 
     /// Commit the data written to the local store.
     fn flush(&self) -> Result<Option<Vec<PathBuf>>> {
+        self.shared_mutabledatastore.as_ref().flush()?;
         self.local_mutabledatastore
             .as_ref()
             .ok_or_else(|| format_err!("flushing a non-local ContentStore is not allowed"))?

eden/scm/lib/revisionstore/src/metadatastore.rs

@@ -125,6 +125,7 @@ impl HgIdMutableHistoryStore for MetadataStore {
     }
 
     fn flush(&self) -> Result<Option<Vec<PathBuf>>> {
+        self.shared_mutablehistorystore.as_ref().flush()?;
         self.local_mutablehistorystore
             .as_ref()
             .ok_or_else(|| format_err!("flushing a non-local MetadataStore is not allowed"))?