add implementation of storage

CMakeLists.txt

@@ -0,0 +1,19 @@
+cmake_minimum_required(VERSION 3.8)
+project(VisualDL)
+
+set(CMAKE_CXX_STANDARD 11)
+
+include_directories(${CMAKE_CURRENT_SOURCE_DIR})
+include_directories(thirdparty/local/include)
+link_directories(thirdparty/local/lib)
+add_subdirectory(thirdparty/pybind11-2.2.1)
+
+set(SOURCE_FILES
+        visualdl/backend/storage/storage.cc visualdl/backend/storage/storage.h
+        visualdl/backend/storage/storage.pb.h
+        visualdl/backend/storage/storage.pb.cc
+        )
+
+add_library(storage visualdl/backend/storage/storage.cc
+            visualdl/backend/storage/storage.pb.cc)
+add_executable(VisualDL ${SOURCE_FILES})

visualdl/backend/storage/storage.cc

@@ -0,0 +1,45 @@
+#include <fstream>
+#include <glog/logging.h>
+
+#include "visualdl/backend/storage/storage.h"
+
+namespace visualdl {
+
+storage::Tablet *Storage::Add(const std::string &tag) {
+  return &proto_.mutable_tablets()->at(tag);
+}
+
+const storage::Tablet *Storage::Find(const std::string &tag) const {
+  auto it = proto_.tablets().find(tag);
+  if (it != proto_.tablets().end()) {
+    return &it->second;
+  }
+  return nullptr;
+}
+
+void Storage::Save(const std::string &path) const {
+  std::ofstream file(path, file.binary | file.out);
+  CHECK(file.is_open()) << "can't open path " << path;
+  auto str = Serialize();
+  file.write(str.c_str(), str.size());
+}
+
+void Storage::Load(const std::string &path) {
+  std::ifstream file(path, file.binary);
+  CHECK(file.is_open()) << "can't open path " << path;
+  size_t size = file.tellg();
+  std::string buffer(size, ' ');
+  file.seekg(0);
+  file.read(&buffer[0], size);
+  DeSerialize(buffer);
+}
+
+std::string Storage::Serialize() const {
+  return proto_.SerializeAsString();
+}
+
+void Storage::DeSerialize(const std::string &data) {
+  proto_.ParseFromString(data);
+}
+
+}  // namespace visualdl

visualdl/backend/storage/storage.h

@@ -1,12 +1,65 @@
 #ifndef VISUALDL_STORAGE_H
 #define VISUALDL_STORAGE_H
 
-class Storage {
+#include <string>
+#include <time.h>
+
+#include "visualdl/backend/storage/storage.pb.h"
+
+namespace visualdl {
+
+class Storage final {
  public:
-  Storage& Global() {
-    static Storage* instance = new Storage();
+  /*
+   * There should be only one Storage instance in memory.
+   */
+  Storage &Global() {
+    static Storage *instance = new Storage();
     return *instance;
   }
+
+  /*
+   * Add a new tablet named `tag`, the newly added instance will be returned.
+   */
+  storage::Tablet *Add(const std::string &tag);
+
+  /*
+   * Search the tablet named `tag`, if not exist, return nullptr.
+   */
+  const storage::Tablet *Find(const std::string &tag) const;
+
+  /*
+   * Serialize this object to string and save it to a file.
+   */
+  void Save(const std::string &path) const;
+
+  /*
+   * Load the Protobuf message from a file.
+   */
+  void Load(const std::string &path);
+
+ protected:
+  /*
+   * Serialize the Storage instance to string.
+   */
+  std::string Serialize() const;
+
+  /*
+   * De-serialize from a string and update this Storage instance.
+   */
+  void DeSerialize(const std::string &data);
+
+  Storage() {
+    // set time stamp
+    time_t time0;
+    time(&time0);
+    proto_.set_timestamp(time0);
+  }
+
+ private:
+  storage::Storage proto_;
 };
 
+} // namespace visualdl
+
 #endif //VISUALDL_STORAGE_H