refactor(db): typedef engine ptr

Former-commit-id: 4629cac435fd484ab949ab112b639a4849e37fca

cpp/src/db/FaissExecutionEngine.cpp

@@ -75,7 +75,7 @@ Status FaissExecutionEngine::Merge(const std::string& location) {
     return Status::OK();
 }
 
-std::shared_ptr<FaissExecutionEngine> FaissExecutionEngine::BuildIndex(const std::string& location) {
+FaissExecutionEngine::Ptr FaissExecutionEngine::BuildIndex(const std::string& location) {
     auto opd = std::make_shared<Operand>();
     opd->d = pIndex_->d;
     opd->index_type = BuildIndexType;
@@ -87,7 +87,7 @@ std::shared_ptr<FaissExecutionEngine> FaissExecutionEngine::BuildIndex(const std
             dynamic_cast<faiss::IndexFlat*>(from_index->index)->xb.data(),
             from_index->id_map.data());
 
-    std::shared_ptr<FaissExecutionEngine> new_ee(new FaissExecutionEngine(index->data(), location));
+    Ptr new_ee(new FaissExecutionEngine(index->data(), location));
     new_ee->Serialize();
     return new_ee;
 }

cpp/src/db/FaissExecutionEngine.h

@@ -13,9 +13,12 @@ namespace zilliz {
 namespace vecwise {
 namespace engine {
 
+class FaissExecutionEngine;
 
 class FaissExecutionEngine : public ExecutionEngine<FaissExecutionEngine> {
 public:
+    typedef std::shared_ptr<FaissExecutionEngine> Ptr;
+
     FaissExecutionEngine(uint16_t dimension, const std::string& location);
     FaissExecutionEngine(std::shared_ptr<faiss::Index> index, const std::string& location);
 
@@ -42,7 +45,7 @@ public:
                   float *distances,
                   long *labels) const;
 
-    std::shared_ptr<FaissExecutionEngine> BuildIndex(const std::string&);
+    FaissExecutionEngine::Ptr BuildIndex(const std::string&);
 
     Status Cache();
 protected:

cpp/src/db/MemManager.h

@@ -22,6 +22,8 @@ namespace meta {
 template <typename EngineT>
 class MemVectors {
 public:
+    typedef typename EngineT::Ptr EnginePtr;
+
     explicit MemVectors(const std::shared_ptr<meta::Meta>&,
             const meta::GroupFileSchema&, const Options&);
 
@@ -46,7 +48,7 @@ private:
     Options options_;
     meta::GroupFileSchema schema_;
     IDGenerator* _pIdGenerator;
-    std::shared_ptr<EngineT> pEE_;
+    EnginePtr pEE_;
 
 }; // MemVectors