feat: add cache for home factory.

include/effective_c++/Lock.h

@@ -28,7 +28,7 @@ namespace effective {
   private:
     //> RAII类只需要一个共享指针成员变量，就可以实现reference-counting copying的行为。
     std::shared_ptr<std::mutex> mutex_ptr_;
-    std::string* users;  // 足够大的一个string数组，存储哪些调用者持有此mutex
+    std::string* users = new std::string[1];  // 足够大的一个string数组，存储哪些调用者持有此mutex
   };
 }  // namespace effective
 #endif  // EFFECTIVE_LOCK_H_

include/effective_c++/home/home_factory.h

@@ -1,8 +1,10 @@
 #pragma once
+#include <memory>
 #ifndef EFFECTIVE_HOME_FACTORY_H_
 #  define EFFECTIVE_HOME_FACTORY_H_
 #  include <iostream>
 #  include <string>
+#  include <unordered_map>
 
 #  include "effective_c++/home/cave.h"
 #  include "effective_c++/home/home.h"
@@ -37,12 +39,26 @@ namespace effective {
     auto makeHome(std::string type) {
       std::unique_ptr<Home, decltype(delHome)> result(nullptr, delHome);
       if (type == "Nest") {
-        result.reset(new Nest());
+        result.reset(new Nest("ParaNest"));
       } else if (type == "Cave") {
         result.reset(new Cave("ParaMountain"));
       }
       return result;
     }
+    /**
+     * @brief Get home by type from cache.
+     * @param type the type of the home.
+     * @return The return type is shared_ptr, it points to a home.
+     */
+    std::shared_ptr<Home> getHome(std::string type);
+    /**
+     * @brief Get the cache size.
+     * @return The return the size of the cache.
+     */
+    int getCacheSize();
+
+  private:
+    std::unordered_map<std::string, std::weak_ptr<Home>> cache;
   };
 }  // namespace effective
 #endif  // EFFECTIVE_HOME_FACTORY_H_

include/effective_c++/home/nest.h

@@ -17,6 +17,12 @@ namespace effective {
     Nest& operator=(Nest&& right) = delete;
     virtual ~Nest() = default;
 
+    /**
+     * @brief Construct the Nest object with address.
+     * @param name The address of the Home.
+     */
+    explicit Nest(std::string address);
+
   private:
     virtual std::string doHealthValue() const override;
     virtual std::string doDraw(int color) const override;

source/effective_c++/home/home_factory.cc

@@ -0,0 +1,17 @@
+#include "effective_c++/home/home_factory.h"
+
+using std::string;
+using namespace effective;
+
+std::shared_ptr<Home> HomeFactory::getHome(std::string type) {
+  // std::weak_ptr::lock 会返回一个shared_ptr
+  auto home_weak_ptr = cache[type];
+  auto home_shared_ptr = home_weak_ptr.lock();
+  if (!home_shared_ptr) {
+    home_shared_ptr = makeHome(type);  // unique_ptr可以赋值给shared_ptr
+    cache[type] = home_shared_ptr;     // shared_ptr可以赋值给weak_ptr
+  }
+  return home_shared_ptr;
+}
+
+int HomeFactory::getCacheSize() { return cache.size(); }

source/effective_c++/home/nest.cc

@@ -1,14 +1,17 @@
 #include "effective_c++/home/nest.h"
 
 using namespace effective;
+using std::string;
 
-std::string Nest::doHealthValue() const { return "check health of full Nest"; }
+Nest::Nest(string address) : Home(address) {}
 
-std::string Nest::doDraw(int color) const {
+string Nest::doHealthValue() const { return "check health of full Nest"; }
+
+string Nest::doDraw(int color) const {
   if (color == 2) {
     return "let paint the house as Blue";
   }
   return "bad color, can not paint.";
 }
 
-std::string Nest::onTick() const { return "My nest address is : " + address_; }
+string Nest::onTick() const { return "My nest address is : " + address_; }

test/source/home_factory_test.cpp

@@ -1,20 +1,28 @@
 #include "effective_c++/home/home_factory.h"
 
 #include "doctest/doctest.h"
-#include "effective_c++/home/home.h"
 
 TEST_CASE("HomeFactory") {
   using namespace effective;
   auto home_factory = HomeFactory();
+
   auto one_cave = home_factory.makeHome("Cave");
   CHECK(one_cave->draw(3) == "let paint the house as Brown");
   CHECK(one_cave->healthValue() == "before check health of full Cave after.");
   CHECK(one_cave->GetAddress("decorate ") == "decorate ParaMountain");
   CHECK(one_cave->GetAddress() == "ParaMountain");
   CHECK(one_cave->boardcastAddress() == "This from home begin send address Tick begin My cave address is : ParaMountainMy cave address is : ParaMountainMy cave address is : ParaMountainend.");
+
   auto one_nest = home_factory.makeHome("Nest");
   CHECK(one_nest->draw(2) == "let paint the house as Blue");
   CHECK(one_nest->healthValue() == "before check health of full Nest after.");
-  CHECK(one_nest->GetAddress("decorate ") == "decorate ");
-  CHECK(one_nest->boardcastAddress() == "This from home begin send address Tick begin My nest address is : My nest address is : My nest address is : end.");
+  CHECK(one_nest->GetAddress("decorate ") == "decorate ParaNest");
+  CHECK(one_nest->boardcastAddress() == "This from home begin send address Tick begin My nest address is : ParaNestMy nest address is : ParaNestMy nest address is : ParaNestend.");
+
+  CHECK(home_factory.getCacheSize() == 0);
+  home_factory.getHome("Cave");
+  home_factory.getHome("Nest");
+  home_factory.getHome("Cave");
+  home_factory.getHome("Nest");
+  CHECK(home_factory.getCacheSize() == 2);
 }