asyncpacks: add AsyncHistoryStore

Summary:
Similarly to AsyncDataStore, this is just a blocking wrapper around a
HistoryStore.

Reviewed By: DurhamG

Differential Revision: D13891140

fbshipit-source-id: 76acadfc1849770b47e2400ce8c70f7e32bba4df

lib/asyncpacks/src/asynchistorystore.rs

@@ -0,0 +1,42 @@
+// Copyright 2019 Facebook, Inc.
+
+use failure::Error;
+use tokio::prelude::*;
+
+use cloned::cloned;
+use revisionstore::{Ancestors, HistoryStore, Key, NodeInfo};
+
+use crate::util::AsyncWrapper;
+
+/// Allow a `HistoryStore` to be used in an asynchronous context
+pub struct AsyncHistoryStore<T: HistoryStore> {
+    history: AsyncWrapper<T>,
+}
+
+impl<T: HistoryStore + Send> AsyncHistoryStore<T> {
+    pub(crate) fn new(store: T) -> Self {
+        AsyncHistoryStore {
+            history: AsyncWrapper::new(store),
+        }
+    }
+
+    /// Asynchronously call the HistoryStore::get_ancestors method.
+    pub fn get_ancestors(&self, key: &Key) -> impl Future<Item = Ancestors, Error = Error> + Send {
+        cloned!(key);
+        self.history.block(move |store| store.get_ancestors(&key))
+    }
+
+    /// Asynchronously call the HistoryStore::get_missing method.
+    pub fn get_missing(
+        &self,
+        keys: Vec<Key>,
+    ) -> impl Future<Item = Vec<Key>, Error = Error> + Send {
+        self.history.block(move |store| store.get_missing(&keys))
+    }
+
+    /// Asynchronously call the HistoryStore::get_node_info method.
+    pub fn get_node_info(&self, key: &Key) -> impl Future<Item = NodeInfo, Error = Error> + Send {
+        cloned!(key);
+        self.history.block(move |store| store.get_node_info(&key))
+    }
+}

lib/asyncpacks/src/lib.rs

@@ -5,8 +5,10 @@ mod util;
 
 pub mod asyncdatapack;
 pub mod asyncdatastore;
+pub mod asynchistorystore;
 pub mod asyncmutabledatapack;
 
 pub use crate::asyncdatapack::AsyncDataPack;
 pub use crate::asyncdatastore::AsyncDataStore;
+pub use crate::asynchistorystore::AsyncHistoryStore;
 pub use crate::asyncmutabledatapack::AsyncMutableDataPack;