Change enum SizeApproximationFlags to enum class (#9604)

Summary:
Change enum SizeApproximationFlags to enum and class and add
overloaded operators for the transition between enum class and uint8_t

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9604

Test Plan: Circle CI jobs

Reviewed By: riversand963

Differential Revision: D34360281

Pulled By: akankshamahajan15

fbshipit-source-id: 6351dfdb717ae3c4530d324c3d37a8ecb01dd1ef

HISTORY.md

@@ -73,6 +73,7 @@
 * `ColumnFamilyOptions::OldDefaults` and `DBOptions::OldDefaults` are marked deprecated, as they are no longer maintained.
 * Add subcompaction callback APIs: `OnSubcompactionBegin()` and `OnSubcompactionCompleted()`.
 * Add file Temperature information to `FileOperationInfo` in event listener API.
+* Change the type of SizeApproximationFlags from enum to enum class. Also update the signature of DB::GetApproximateSizes API from uint8_t to SizeApproximationFlags.
 * Add Temperature hints information from RocksDB in API `NewSequentialFile()`. backup and checkpoint operations need to open the source files with `NewSequentialFile()`, which will have the temperature hints. Other operations are not covered.
 
 ### Behavior Changes

include/rocksdb/db.h

@@ -1114,7 +1114,7 @@ class DB {
 
   // Flags for DB::GetSizeApproximation that specify whether memtable
   // stats should be included, or file stats approximation or both
-  enum SizeApproximationFlags : uint8_t {
+  enum class SizeApproximationFlags : uint8_t {
     NONE = 0,
     INCLUDE_MEMTABLES = 1 << 0,
     INCLUDE_FILES = 1 << 1
@@ -1138,17 +1138,13 @@ class DB {
   virtual Status GetApproximateSizes(ColumnFamilyHandle* column_family,
                                      const Range* ranges, int n,
                                      uint64_t* sizes,
-                                     uint8_t include_flags = INCLUDE_FILES) {
-    SizeApproximationOptions options;
-    options.include_memtables =
-        (include_flags & SizeApproximationFlags::INCLUDE_MEMTABLES) != 0;
-    options.include_files =
-        (include_flags & SizeApproximationFlags::INCLUDE_FILES) != 0;
-    return GetApproximateSizes(options, column_family, ranges, n, sizes);
-  }
-  virtual Status GetApproximateSizes(const Range* ranges, int n,
-                                     uint64_t* sizes,
-                                     uint8_t include_flags = INCLUDE_FILES) {
+                                     SizeApproximationFlags include_flags =
+                                         SizeApproximationFlags::INCLUDE_FILES);
+
+  virtual Status GetApproximateSizes(
+      const Range* ranges, int n, uint64_t* sizes,
+      SizeApproximationFlags include_flags =
+          SizeApproximationFlags::INCLUDE_FILES) {
     return GetApproximateSizes(DefaultColumnFamily(), ranges, n, sizes,
                                include_flags);
   }
@@ -1671,6 +1667,32 @@ class DB {
 #endif  // !ROCKSDB_LITE
 };
 
+// Overloaded operators for enum class SizeApproximationFlags.
+inline DB::SizeApproximationFlags operator&(DB::SizeApproximationFlags lhs,
+                                            DB::SizeApproximationFlags rhs) {
+  return static_cast<DB::SizeApproximationFlags>(static_cast<uint8_t>(lhs) &
+                                                 static_cast<uint8_t>(rhs));
+}
+inline DB::SizeApproximationFlags operator|(DB::SizeApproximationFlags lhs,
+                                            DB::SizeApproximationFlags rhs) {
+  return static_cast<DB::SizeApproximationFlags>(static_cast<uint8_t>(lhs) |
+                                                 static_cast<uint8_t>(rhs));
+}
+
+inline Status DB::GetApproximateSizes(ColumnFamilyHandle* column_family,
+                                      const Range* ranges, int n,
+                                      uint64_t* sizes,
+                                      SizeApproximationFlags include_flags) {
+  SizeApproximationOptions options;
+  options.include_memtables =
+      ((include_flags & SizeApproximationFlags::INCLUDE_MEMTABLES) !=
+       SizeApproximationFlags::NONE);
+  options.include_files =
+      ((include_flags & SizeApproximationFlags::INCLUDE_FILES) !=
+       SizeApproximationFlags::NONE);
+  return GetApproximateSizes(options, column_family, ranges, n, sizes);
+}
+
 // Destroy the contents of the specified database.
 // Be very careful using this method.
 Status DestroyDB(const std::string& name, const Options& options,

java/rocksjni/rocksjni.cc

@@ -2725,9 +2725,22 @@ jlongArray Java_org_rocksdb_RocksDB_getApproximateSizes(
   }
 
   auto sizes = std::unique_ptr<uint64_t[]>(new uint64_t[range_count]);
+
+  ROCKSDB_NAMESPACE::DB::SizeApproximationFlags include_flags =
+      ROCKSDB_NAMESPACE::DB::SizeApproximationFlags::NONE;
+  if (jinclude_flags & 1) {
+    include_flags =
+        ROCKSDB_NAMESPACE::DB::SizeApproximationFlags::INCLUDE_MEMTABLES;
+  }
+  if (jinclude_flags & 2) {
+    include_flags =
+        (include_flags |
+         ROCKSDB_NAMESPACE::DB::SizeApproximationFlags::INCLUDE_FILES);
+  }
+
   db->GetApproximateSizes(cf_handle, ranges.get(),
                           static_cast<int>(range_count), sizes.get(),
-      static_cast<uint8_t>(jinclude_flags));
+                          include_flags);
 
   // release LongArrayElements
   env->ReleaseLongArrayElements(jrange_slice_handles, jranges, JNI_ABORT);