Fix readonly db

Summary:
DBImplReadOnly::CompactRange wasn't override DBImpl::CompactRange;
this can cause problem when using StackableDB inheritors like
DbWithTtl.
P. S. Thanks C++11 for override :)

Test Plan: make all check

Reviewers: igor, sdong

Reviewed By: sdong

Subscribers: yhchiang, leveldb

Differential Revision: https://reviews.facebook.net/D20829

db/db_impl_readonly.h

@@ -32,60 +32,62 @@ class DBImplReadOnly : public DBImpl {
   using DB::Get;
   virtual Status Get(const ReadOptions& options,
                      ColumnFamilyHandle* column_family, const Slice& key,
-                     std::string* value);
+                     std::string* value) override;
 
   // TODO: Implement ReadOnly MultiGet?
 
   using DBImpl::NewIterator;
   virtual Iterator* NewIterator(const ReadOptions&,
-                                ColumnFamilyHandle* column_family);
+                                ColumnFamilyHandle* column_family) override;
 
   virtual Status NewIterators(
       const ReadOptions& options,
       const std::vector<ColumnFamilyHandle*>& column_families,
-      std::vector<Iterator*>* iterators);
+      std::vector<Iterator*>* iterators) override;
 
   using DBImpl::Put;
   virtual Status Put(const WriteOptions& options,
                      ColumnFamilyHandle* column_family, const Slice& key,
-                     const Slice& value) {
+                     const Slice& value) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
   using DBImpl::Merge;
   virtual Status Merge(const WriteOptions& options,
                        ColumnFamilyHandle* column_family, const Slice& key,
-                       const Slice& value) {
+                       const Slice& value) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
   using DBImpl::Delete;
   virtual Status Delete(const WriteOptions& options,
-                        ColumnFamilyHandle* column_family, const Slice& key) {
+                        ColumnFamilyHandle* column_family,
+                        const Slice& key) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
-  virtual Status Write(const WriteOptions& options, WriteBatch* updates) {
+  virtual Status Write(const WriteOptions& options,
+                       WriteBatch* updates) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
   using DBImpl::CompactRange;
   virtual Status CompactRange(ColumnFamilyHandle* column_family,
                               const Slice* begin, const Slice* end,
-                              bool reduce_level = false,
-                              int target_level = -1) {
+                              bool reduce_level = false, int target_level = -1,
+                              uint32_t target_path_id = 0) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
-  virtual Status DisableFileDeletions() {
+  virtual Status DisableFileDeletions() override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
-  virtual Status EnableFileDeletions(bool force) {
+  virtual Status EnableFileDeletions(bool force) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
   virtual Status GetLiveFiles(std::vector<std::string>&,
                               uint64_t* manifest_file_size,
-                              bool flush_memtable = true) {
+                              bool flush_memtable = true) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
   using DBImpl::Flush;
   virtual Status Flush(const FlushOptions& options,
-                       ColumnFamilyHandle* column_family) {
+                       ColumnFamilyHandle* column_family) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }