C++: Add shared test headers to emulate standard library types

Dave Bartolomeo · Dave Bartolomeo · commit 45968efd283d · 2021-04-20T18:21:50.000-04:00
diff --git a/cpp/ql/test/include/memory.h b/cpp/ql/test/include/memory.h
@@ -0,0 +1,137 @@
+#if !defined(CODEQL_MEMORY_H)
+#define CODEQL_MEMORY_H
+
+namespace std {
+  namespace detail {
+    template<typename T>
+    class compressed_pair_element {
+      T element;
+
+    public:
+      compressed_pair_element() = default;
+      compressed_pair_element(const T& t) : element(t) {}
+      
+      T& get() { return element; }
+
+      const T& get() const { return element; }
+    };
+
+    template<typename T, typename U>
+    struct compressed_pair : private compressed_pair_element<T>, private compressed_pair_element<U> {
+      compressed_pair() = default;
+      compressed_pair(T& t) : compressed_pair_element<T>(t), compressed_pair_element<U>() {}
+      compressed_pair(const compressed_pair&) = delete;
+      compressed_pair(compressed_pair<T, U>&&) noexcept = default;
+
+      T& first() { return static_cast<compressed_pair_element<T>&>(*this).get(); }
+      U& second() { return static_cast<compressed_pair_element<U>&>(*this).get(); }
+
+      const T& first() const { return static_cast<const compressed_pair_element<T>&>(*this).get(); }
+      const U& second() const { return static_cast<const compressed_pair_element<U>&>(*this).get(); }
+    };
+  }
+
+  template<class T>
+  struct default_delete {
+    void operator()(T* ptr) const { delete ptr; }
+  };
+
+  template<class T>
+  struct default_delete<T[]> {
+    template<class U>
+    void operator()(U* ptr) const { delete[] ptr; }
+  };
+
+  template<class T, class Deleter = default_delete<T> >
+  class unique_ptr {
+  private:
+    detail::compressed_pair<T*, Deleter> data;
+  public:
+    constexpr unique_ptr() noexcept {}
+    explicit unique_ptr(T* ptr) noexcept : data(ptr) {}
+    unique_ptr(const unique_ptr& ptr) = delete;
+    unique_ptr(unique_ptr&& ptr) noexcept = default;
+
+    unique_ptr& operator=(unique_ptr&& ptr) noexcept = default;
+
+    T& operator*() const { return *get(); }
+    T* operator->() const noexcept { return get(); }
+
+    T* get() const noexcept { return data.first(); }
+    T* release() noexcept { 
+        Deleter& d = data.second();
+        d(data.first());
+        data.first() = nullptr;
+    }
+
+    ~unique_ptr() {
+      Deleter& d = data.second();
+      d(data.first());
+    }
+  };
+  
+  template<typename T, class... Args> unique_ptr<T> make_unique(Args&&... args) {
+    return unique_ptr<T>(new T(args...)); // std::forward calls elided for simplicity.
+  }
+
+  class ctrl_block {
+    unsigned uses;
+
+  public:
+    ctrl_block() : uses(1) {}
+
+    void inc() { ++uses; }
+    bool dec() { return --uses == 0; }
+
+    virtual void destroy() = 0;
+    virtual ~ctrl_block() {}
+  };
+
+  template<typename T, class Deleter = default_delete<T> >
+  struct ctrl_block_impl: public ctrl_block {
+    T* ptr;
+    Deleter d;
+
+    ctrl_block_impl(T* ptr, Deleter d) : ptr(ptr), d(d) {}
+    virtual void destroy() override { d(ptr); }
+  };
+
+  template<class T>
+  class shared_ptr {
+  private:
+    ctrl_block* ctrl;
+    T* ptr;
+
+    void dec() {
+      if(ctrl->dec()) {
+        ctrl->destroy();
+        delete ctrl;
+      }
+    }
+
+    void inc() {
+      ctrl->inc();
+    }
+
+  public:
+    constexpr shared_ptr() noexcept = default;
+    shared_ptr(T* ptr) : ctrl(new ctrl_block_impl<T>(ptr, default_delete<T>())) {}
+    shared_ptr(const shared_ptr& s) noexcept : ptr(s.ptr), ctrl(s.ctrl) {
+      inc();
+    }
+    shared_ptr(shared_ptr&& s) noexcept = default;
+    shared_ptr(unique_ptr<T>&& s) : shared_ptr(s.release()) {
+    }
+    T* operator->() const { return ptr; }
+
+    T& operator*() const { return *ptr; }
+
+    ~shared_ptr() { dec(); }
+  };
+
+  template<typename T, class... Args> shared_ptr<T> make_shared(Args&&... args) {
+    return shared_ptr<T>(new T(args...)); // std::forward calls elided for simplicity.
+  }
+}
+
+#endif
diff --git a/cpp/ql/test/include/type_traits.h b/cpp/ql/test/include/type_traits.h
@@ -0,0 +1,21 @@
+#if !defined(CODEQL_TYPE_TRAITS_H)
+#define CODEQL_TYPE_TRAITS_H
+
+namespace std {
+    template<typename T>
+    struct remove_reference {
+        typedef T type;
+    };
+
+    template<typename T>
+    struct remove_reference<T&> {
+        typedef T type;
+    };
+
+    template<typename T>
+    struct remove_reference<T&&> {
+        typedef T type;
+    };
+}
+
+#endif
diff --git a/cpp/ql/test/include/utility.h b/cpp/ql/test/include/utility.h
@@ -0,0 +1,13 @@
+#if !defined(CODEQL_UTILITY_H)
+#define CODEQL_UTILITY_H
+
+#include "type_traits.h"
+
+namespace std {
+    template<typename T>
+    typename remove_reference<T>::type&& move(T&& src) {
+        return static_cast<typename remove_reference<T>::type&&>(src);
+    }
+}
+
+#endif
