support bazel complie this project and format code.

learn_class/modern_cpp_30/smart_ptr/auto_scope.cpp

@@ -0,0 +1,102 @@
+//
+// Created by light on 19-12-9.
+//
+#include "../RAII/shape.h"
+template <typename T> class auto_ptr {
+public:
+  explicit auto_ptr(T *ptr = nullptr) noexcept : ptr_(ptr) {}
+
+  ~auto_ptr() noexcept { delete ptr_; }
+
+  T &operator*() const noexcept { return *ptr_; }
+
+  T *operator->() const noexcept { return ptr_; }
+
+  operator bool() const noexcept { return ptr_; }
+
+  T *get() const noexcept { return ptr_; }
+
+  // 拷贝构造,被复制放释放原来指针的所有权,交给复制方
+  // 始终只有一个对象管理一块空间
+  auto_ptr(auto_ptr &other) noexcept { ptr_ = other.release(); }
+
+  // copy and swap  始终只有一个对象有管理这块空间的权限
+  auto_ptr &operator=(auto_ptr &rhs) noexcept {
+    //        auto_ptr tmp(rhs.release());
+    //        tmp.swap(*this);
+    // s上述两行等价于下面一行
+    auto_ptr(rhs.release()).swap(*this);
+    return *this;
+  }
+
+  // 原来的指针释放所有权
+  T *release() noexcept {
+    T *ptr = ptr_;
+    ptr_ = nullptr;
+    return ptr;
+  }
+
+  void swap(auto_ptr &rhs) noexcept {
+    using std::swap;
+    swap(ptr_, rhs.ptr_); // 转移指针所有权
+  }
+
+private:
+  T *ptr_;
+};
+
+template <typename T> void swap(auto_ptr<T> &lhs, auto_ptr<T> &rhs) noexcept {
+  lhs.swap(rhs);
+}
+
+template <class T>
+class scoped_ptr // noncopyable
+{
+
+public:
+  explicit scoped_ptr(T *ptr = 0) noexcept : ptr_(ptr) {}
+
+  ~scoped_ptr() noexcept { delete ptr_; }
+
+  void reset(T *p = 0) noexcept { scoped_ptr(p).swap(*this); }
+
+  T &operator*() const noexcept { return *ptr_; }
+
+  T *operator->() const noexcept { return ptr_; }
+
+  T *get() const noexcept { return ptr_; }
+
+  void swap(scoped_ptr &rhs) noexcept {
+    using std::swap;
+    swap(ptr_, rhs.ptr_);
+  }
+
+private:
+  T *ptr_;
+
+  scoped_ptr(scoped_ptr const &);
+  scoped_ptr &operator=(scoped_ptr const &);
+};
+
+template <typename T>
+void swap(scoped_ptr<T> &lhs, scoped_ptr<T> &rhs) noexcept {
+  lhs.swap(rhs);
+}
+
+int main() {
+  auto_ptr<shape> ptr1{create_shape(shape_type::circle)};
+  auto_ptr<shape> ptr2{ptr1};
+  if (ptr1.get() == nullptr && ptr2.get())
+    cout << "拷贝构造：ptr1释放了所有权,ptr2获得了所有权" << endl;
+  ptr1 = ptr1;
+
+  auto_ptr<shape> ptr3{create_shape(shape_type::rectangle)};
+  ptr1 = ptr3;
+  if (ptr3.get() == nullptr && ptr1.get())
+    cout << "赋值操作：始终只有一个对象管理一个区块!ptr3释放了所有权,"
+            "ptr1获得了所有权"
+         << endl;
+
+  scoped_ptr<shape> sptr1{create_shape(shape_type::circle)};
+  //    scoped_ptr<shape> sptr2{sptr1};       // error  不可拷贝
+}