backingstore: rename refresh method to flush

Summary:
The intent behind the refresh method is to both read new data from the disk,
but also to flush the in-memory write buffer to disk. The name "flush" is used
in the revisionstore code to mean the latter, thus let's use "flush" in the
rest of the codebase.

Reviewed By: kmancini

Differential Revision: D30947873

fbshipit-source-id: c85a6abe770a47d6ce454d6af1fa73e505194a22

eden/fs/store/hg/HgBackingStore.cpp

@@ -770,7 +770,7 @@ HgBackingStore::getLiveImportWatches(HgImportObject object) const {
 }
 
 void HgBackingStore::periodicManagementTask() {
-  datapackStore_.refresh();
+  datapackStore_.flush();
 }
 
 } // namespace facebook::eden

eden/fs/store/hg/HgDatapackStore.cpp

@@ -225,7 +225,7 @@ std::unique_ptr<Tree> HgDatapackStore::getTree(
   if (!tree && local_only) {
     // Mercurial might have just written the tree to the store. Refresh the
     // store and try again, this time allowing remote fetches.
-    store_.refresh();
+    store_.flush();
     tree = store_.getTree(manifestId.getBytes(), false);
   }
   if (tree) {
@@ -234,8 +234,8 @@ std::unique_ptr<Tree> HgDatapackStore::getTree(
   return nullptr;
 }
 
-void HgDatapackStore::refresh() {
-  store_.refresh();
+void HgDatapackStore::flush() {
+  store_.flush();
 }
 
 } // namespace facebook::eden

eden/fs/store/hg/HgDatapackStore.h

@@ -61,7 +61,13 @@ class HgDatapackStore {
       const Hash& edenTreeId,
       LocalStore::WriteBatch* writeBatch);
 
-  void refresh();
+  /**
+   * Flush any pending writes to disk.
+   *
+   * As a side effect, this also reloads the current state of Mercurial's
+   * cache, picking up any writes done by Mercurial.
+   */
+  void flush();
 
  private:
   HgNativeBackingStore store_;

eden/scm/lib/backingstore/c_api/HgNativeBackingStore.cpp

@@ -271,10 +271,10 @@ std::shared_ptr<RustTree> HgNativeBackingStore::getTree(
   return manifest.unwrap();
 }
 
-void HgNativeBackingStore::refresh() {
-  XLOG(DBG7) << "Refreshing backing store";
+void HgNativeBackingStore::flush() {
+  XLOG(DBG7) << "Flushing backing store";
 
-  rust_backingstore_refresh(store_.get());
+  rust_backingstore_flush(store_.get());
 }
 
 } // namespace facebook::eden

eden/scm/lib/backingstore/c_api/HgNativeBackingStore.h

@@ -50,7 +50,7 @@ class HgNativeBackingStore {
 
   std::shared_ptr<RustTree> getTree(folly::ByteRange node, bool local);
 
-  void refresh();
+  void flush();
 
  private:
   std::unique_ptr<RustBackingStore, std::function<void(RustBackingStore*)>>

eden/scm/lib/backingstore/c_api/RustBackingStore.h

@@ -7,7 +7,7 @@
  * This file is generated with cbindgen. Please run `./tools/cbindgen.sh` to
  * update this file.
  *
- * @generated SignedSource<<d55c0fa3a07268a77cb8b9aee5ec761e>>
+ * @generated SignedSource<<50807b13cfd41d6c06ab43ae99fb8ea1>>
  *
  */
 
@@ -160,7 +160,7 @@ void rust_backingstore_get_tree_batch(RustBackingStore *store,
 
 void rust_tree_free(RustTree *tree);
 
-void rust_backingstore_refresh(RustBackingStore *store);
+void rust_backingstore_flush(RustBackingStore *store);
 
 void rust_cbytes_free(RustCBytes *vec);
 

eden/scm/lib/backingstore/src/backingstore/contentstores.rs

@@ -240,7 +240,7 @@ impl BackingContentStores {
 
     /// Forces backing store to rescan pack files or local indexes
     #[instrument(level = "debug", skip(self))]
-    pub fn refresh(&self) {
+    pub fn flush(&self) {
         self.blobstore.refresh().ok();
         self.treestore.as_content_store().refresh().ok();
     }

eden/scm/lib/backingstore/src/backingstore/mod.rs

@@ -82,10 +82,10 @@ impl BackingStore {
 
     /// Forces backing store to write its pending data to disk and to read the latest version from
     /// the disk.
-    pub fn refresh(&self) {
+    pub fn flush(&self) {
         match self {
-            Old(stores) => stores.refresh(),
-            New(stores) => stores.refresh(),
+            Old(stores) => stores.flush(),
+            New(stores) => stores.flush(),
         }
     }
 }
@@ -93,6 +93,6 @@ impl BackingStore {
 impl Drop for BackingStore {
     fn drop(&mut self) {
         // Make sure that all the data that was fetched is written to the hgcache.
-        self.refresh();
+        self.flush();
     }
 }

eden/scm/lib/backingstore/src/backingstore/scmstores.rs

@@ -264,7 +264,7 @@ impl BackingScmStores {
 
     /// Forces backing store to rescan pack files or local indexes
     #[instrument(level = "debug", skip(self))]
-    pub fn refresh(&self) {
+    pub fn flush(&self) {
         self.filestore.refresh().ok();
         self.treestore.refresh().ok();
     }

eden/scm/lib/backingstore/src/raw/backingstore.rs

@@ -170,9 +170,9 @@ pub extern "C" fn rust_tree_free(tree: *mut Tree) {
 }
 
 #[no_mangle]
-pub extern "C" fn rust_backingstore_refresh(store: *mut BackingStore) {
+pub extern "C" fn rust_backingstore_flush(store: *mut BackingStore) {
     assert!(!store.is_null());
     let store = unsafe { &*store };
 
-    store.refresh();
+    store.flush();
 }