refactor(db): typdef meta ptr

Former-commit-id: 1fcbd80c65a1ee2815a57127f04807ce7d9f23f3

cpp/src/db/DBImpl.h

@@ -21,6 +21,8 @@ namespace meta {
 template <typename EngineT>
 class DBImpl : public DB {
 public:
+    typedef typename meta::Meta::Ptr MetaPtr;
+
     DBImpl(const Options& options);
 
     virtual Status add_group(meta::GroupSchema& group_info) override;
@@ -78,7 +80,7 @@ private:
     bool bg_build_index_started_;
     std::condition_variable bg_build_index_finish_signal_;
 
-    std::shared_ptr<meta::Meta> _pMeta;
+    MetaPtr _pMeta;
     std::shared_ptr<MemManagerT> _pMemMgr;
 
 }; // DBImpl

cpp/src/db/MemManager.h

@@ -23,6 +23,7 @@ template <typename EngineT>
 class MemVectors {
 public:
     typedef typename EngineT::Ptr EnginePtr;
+    typedef typename meta::Meta::Ptr MetaPtr;
 
     explicit MemVectors(const std::shared_ptr<meta::Meta>&,
             const meta::GroupFileSchema&, const Options&);
@@ -44,7 +45,7 @@ private:
     MemVectors(const MemVectors&) = delete;
     MemVectors& operator=(const MemVectors&) = delete;
 
-    std::shared_ptr<meta::Meta> pMeta_;
+    MetaPtr pMeta_;
     Options options_;
     meta::GroupFileSchema schema_;
     IDGenerator* _pIdGenerator;
@@ -59,6 +60,7 @@ class MemManager {
 public:
     typedef MemVectors<EngineT> ItemT;
     typedef std::shared_ptr<ItemT> VectorsPtr;
+    typedef typename meta::Meta::Ptr MetaPtr;
 
     MemManager(const std::shared_ptr<meta::Meta>& meta_, const Options& options)
         : _pMeta(meta_), options_(options) {}
@@ -79,7 +81,7 @@ private:
     typedef std::vector<VectorsPtr> ImmMemPool;
     MemMap _memMap;
     ImmMemPool _immMems;
-    std::shared_ptr<meta::Meta> _pMeta;
+    MetaPtr _pMeta;
     Options options_;
     std::mutex _mutex;
     std::mutex serialization_mtx_;

cpp/src/db/Meta.h

@@ -5,6 +5,8 @@
 #include <vector>
 #include <map>
 #include <ctime>
+#include <memory>
+
 #include "Options.h"
 #include "Status.h"
 
@@ -50,8 +52,11 @@ typedef std::vector<GroupFileSchema> GroupFilesSchema;
 typedef std::map<DateT, GroupFilesSchema> DatePartionedGroupFilesSchema;
 
 
+class Meta;
 class Meta {
 public:
+    typedef std::shared_ptr<Meta> Ptr;
+
     virtual Status add_group(GroupSchema& group_info) = 0;
     virtual Status get_group(GroupSchema& group_info) = 0;
     virtual Status has_group(const std::string& group_id_, bool& has_or_not_) = 0;