Move base to DEPS

base/memory/ref_counted.h

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef BASE_MEMORY_REF_COUNTED_H_
-#define BASE_MEMORY_REF_COUNTED_H_
-
-#include <cassert>
-#include <iosfwd>
-
-#include "base/atomic_ref_count.h"
-#include "base/base_export.h"
-#include "base/compiler_specific.h"
-#ifndef NDEBUG
-#include "base/logging.h"
-#endif
-#include "base/move.h"
-#include "base/threading/thread_collision_warner.h"
-#include "build/build_config.h"
-
-namespace base {
-
-namespace subtle {
-
-class BASE_EXPORT RefCountedBase {
- public:
-  bool HasOneRef() const { return ref_count_ == 1; }
-
- protected:
-  RefCountedBase()
-      : ref_count_(0)
-  #ifndef NDEBUG
-      , in_dtor_(false)
-  #endif
-      {
-  }
-
-  ~RefCountedBase() {
-  #ifndef NDEBUG
-    DCHECK(in_dtor_) << "RefCounted object deleted without calling Release()";
-  #endif
-  }
-
-
-  void AddRef() const {
-    // TODO(maruel): Add back once it doesn't assert 500 times/sec.
-    // Current thread books the critical section "AddRelease"
-    // without release it.
-    // DFAKE_SCOPED_LOCK_THREAD_LOCKED(add_release_);
-  #ifndef NDEBUG
-    DCHECK(!in_dtor_);
-  #endif
-    ++ref_count_;
-  }
-
-  // Returns true if the object should self-delete.
-  bool Release() const {
-    // TODO(maruel): Add back once it doesn't assert 500 times/sec.
-    // Current thread books the critical section "AddRelease"
-    // without release it.
-    // DFAKE_SCOPED_LOCK_THREAD_LOCKED(add_release_);
-  #ifndef NDEBUG
-    DCHECK(!in_dtor_);
-  #endif
-    if (--ref_count_ == 0) {
-  #ifndef NDEBUG
-      in_dtor_ = true;
-  #endif
-      return true;
-    }
-    return false;
-  }
-
- private:
-  mutable int ref_count_;
-#ifndef NDEBUG
-  mutable bool in_dtor_;
-#endif
-
-  DFAKE_MUTEX(add_release_);
-
-  DISALLOW_COPY_AND_ASSIGN(RefCountedBase);
-};
-
-class BASE_EXPORT RefCountedThreadSafeBase {
- public:
-  bool HasOneRef() const;
-
- protected:
-  RefCountedThreadSafeBase();
-  ~RefCountedThreadSafeBase();
-
-  void AddRef() const;
-
-  // Returns true if the object should self-delete.
-  bool Release() const;
-
- private:
-  mutable AtomicRefCount ref_count_;
-#ifndef NDEBUG
-  mutable bool in_dtor_;
-#endif
-
-  DISALLOW_COPY_AND_ASSIGN(RefCountedThreadSafeBase);
-};
-
-}  // namespace subtle
-
-//
-// A base class for reference counted classes.  Otherwise, known as a cheap
-// knock-off of WebKit's RefCounted<T> class.  To use this guy just extend your
-// class from it like so:
-//
-//   class MyFoo : public base::RefCounted<MyFoo> {
-//    ...
-//    private:
-//     friend class base::RefCounted<MyFoo>;
-//     ~MyFoo();
-//   };
-//
-// You should always make your destructor private, to avoid any code deleting
-// the object accidently while there are references to it.
-template <class T>
-class RefCounted : public subtle::RefCountedBase {
- public:
-  RefCounted() {}
-
-  void AddRef() const {
-    subtle::RefCountedBase::AddRef();
-  }
-
-  void Release() const {
-    if (subtle::RefCountedBase::Release()) {
-      delete static_cast<const T*>(this);
-    }
-  }
-
- protected:
-  ~RefCounted() {}
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(RefCounted<T>);
-};
-
-// Forward declaration.
-template <class T, typename Traits> class RefCountedThreadSafe;
-
-// Default traits for RefCountedThreadSafe<T>.  Deletes the object when its ref
-// count reaches 0.  Overload to delete it on a different thread etc.
-template<typename T>
-struct DefaultRefCountedThreadSafeTraits {
-  static void Destruct(const T* x) {
-    // Delete through RefCountedThreadSafe to make child classes only need to be
-    // friend with RefCountedThreadSafe instead of this struct, which is an
-    // implementation detail.
-    RefCountedThreadSafe<T,
-                         DefaultRefCountedThreadSafeTraits>::DeleteInternal(x);
-  }
-};
-
-//
-// A thread-safe variant of RefCounted<T>
-//
-//   class MyFoo : public base::RefCountedThreadSafe<MyFoo> {
-//    ...
-//   };
-//
-// If you're using the default trait, then you should add compile time
-// asserts that no one else is deleting your object.  i.e.
-//    private:
-//     friend class base::RefCountedThreadSafe<MyFoo>;
-//     ~MyFoo();
-template <class T, typename Traits = DefaultRefCountedThreadSafeTraits<T> >
-class RefCountedThreadSafe : public subtle::RefCountedThreadSafeBase {
- public:
-  RefCountedThreadSafe() {}
-
-  void AddRef() const {
-    subtle::RefCountedThreadSafeBase::AddRef();
-  }
-
-  void Release() const {
-    if (subtle::RefCountedThreadSafeBase::Release()) {
-      Traits::Destruct(static_cast<const T*>(this));
-    }
-  }
-
- protected:
-  ~RefCountedThreadSafe() {}
-
- private:
-  friend struct DefaultRefCountedThreadSafeTraits<T>;
-  static void DeleteInternal(const T* x) { delete x; }
-
-  DISALLOW_COPY_AND_ASSIGN(RefCountedThreadSafe);
-};
-
-//
-// A thread-safe wrapper for some piece of data so we can place other
-// things in scoped_refptrs<>.
-//
-template<typename T>
-class RefCountedData
-    : public base::RefCountedThreadSafe< base::RefCountedData<T> > {
- public:
-  RefCountedData() : data() {}
-  RefCountedData(const T& in_value) : data(in_value) {}
-
-  T data;
-
- private:
-  friend class base::RefCountedThreadSafe<base::RefCountedData<T> >;
-  ~RefCountedData() {}
-};
-
-}  // namespace base
-
-//
-// A smart pointer class for reference counted objects.  Use this class instead
-// of calling AddRef and Release manually on a reference counted object to
-// avoid common memory leaks caused by forgetting to Release an object
-// reference.  Sample usage:
-//
-//   class MyFoo : public RefCounted<MyFoo> {
-//    ...
-//   };
-//
-//   void some_function() {
-//     scoped_refptr<MyFoo> foo = new MyFoo();
-//     foo->Method(param);
-//     // |foo| is released when this function returns
-//   }
-//
-//   void some_other_function() {
-//     scoped_refptr<MyFoo> foo = new MyFoo();
-//     ...
-//     foo = NULL;  // explicitly releases |foo|
-//     ...
-//     if (foo)
-//       foo->Method(param);
-//   }
-//
-// The above examples show how scoped_refptr<T> acts like a pointer to T.
-// Given two scoped_refptr<T> classes, it is also possible to exchange
-// references between the two objects, like so:
-//
-//   {
-//     scoped_refptr<MyFoo> a = new MyFoo();
-//     scoped_refptr<MyFoo> b;
-//
-//     b.swap(a);
-//     // now, |b| references the MyFoo object, and |a| references NULL.
-//   }
-//
-// To make both |a| and |b| in the above example reference the same MyFoo
-// object, simply use the assignment operator:
-//
-//   {
-//     scoped_refptr<MyFoo> a = new MyFoo();
-//     scoped_refptr<MyFoo> b;
-//
-//     b = a;
-//     // now, |a| and |b| each own a reference to the same MyFoo object.
-//   }
-//
-template <class T>
-class scoped_refptr {
-  TYPE_WITH_MOVE_CONSTRUCTOR_FOR_CPP_03(scoped_refptr)
- public:
-  typedef T element_type;
-
-  scoped_refptr() : ptr_(NULL) {
-  }
-
-  scoped_refptr(T* p) : ptr_(p) {
-    if (ptr_)
-      AddRef(ptr_);
-  }
-
-  scoped_refptr(const scoped_refptr<T>& r) : ptr_(r.ptr_) {
-    if (ptr_)
-      AddRef(ptr_);
-  }
-
-  template <typename U>
-  scoped_refptr(const scoped_refptr<U>& r) : ptr_(r.get()) {
-    if (ptr_)
-      AddRef(ptr_);
-  }
-
-  template <typename U>
-  scoped_refptr(scoped_refptr<U>&& r) : ptr_(r.get()) {
-    r.ptr_ = nullptr;
-  }
-
-  ~scoped_refptr() {
-    if (ptr_)
-      Release(ptr_);
-  }
-
-  T* get() const { return ptr_; }
-
-  T& operator*() const {
-    assert(ptr_ != NULL);
-    return *ptr_;
-  }
-
-  T* operator->() const {
-    assert(ptr_ != NULL);
-    return ptr_;
-  }
-
-  scoped_refptr<T>& operator=(T* p) {
-    // AddRef first so that self assignment should work
-    if (p)
-      AddRef(p);
-    T* old_ptr = ptr_;
-    ptr_ = p;
-    if (old_ptr)
-      Release(old_ptr);
-    return *this;
-  }
-
-  scoped_refptr<T>& operator=(const scoped_refptr<T>& r) {
-    return *this = r.ptr_;
-  }
-
-  template <typename U>
-  scoped_refptr<T>& operator=(const scoped_refptr<U>& r) {
-    return *this = r.get();
-  }
-
-  scoped_refptr<T>& operator=(scoped_refptr<T>&& r) {
-    scoped_refptr<T>(r.Pass()).swap(*this);
-    return *this;
-  }
-
-  template <typename U>
-  scoped_refptr<T>& operator=(scoped_refptr<U>&& r) {
-    scoped_refptr<T>(r.Pass()).swap(*this);
-    return *this;
-  }
-
-  void swap(T** pp) {
-    T* p = ptr_;
-    ptr_ = *pp;
-    *pp = p;
-  }
-
-  void swap(scoped_refptr<T>& r) {
-    swap(&r.ptr_);
-  }
-
- private:
-  template <typename U> friend class scoped_refptr;
-
-  // Allow scoped_refptr<T> to be used in boolean expressions, but not
-  // implicitly convertible to a real bool (which is dangerous).
-  //
-  // Note that this trick is only safe when the == and != operators
-  // are declared explicitly, as otherwise "refptr1 == refptr2"
-  // will compile but do the wrong thing (i.e., convert to Testable
-  // and then do the comparison).
-  typedef T* scoped_refptr::*Testable;
-
- public:
-  operator Testable() const { return ptr_ ? &scoped_refptr::ptr_ : nullptr; }
-
-  template <typename U>
-  bool operator==(const scoped_refptr<U>& rhs) const {
-    return ptr_ == rhs.get();
-  }
-
-  template <typename U>
-  bool operator!=(const scoped_refptr<U>& rhs) const {
-    return !operator==(rhs);
-  }
-
-  template <typename U>
-  bool operator<(const scoped_refptr<U>& rhs) const {
-    return ptr_ < rhs.get();
-  }
-
- protected:
-  T* ptr_;
-
- private:
-  // Non-inline helpers to allow:
-  //     class Opaque;
-  //     extern template class scoped_refptr<Opaque>;
-  // Otherwise the compiler will complain that Opaque is an incomplete type.
-  static void AddRef(T* ptr);
-  static void Release(T* ptr);
-};
-
-template <typename T>
-void scoped_refptr<T>::AddRef(T* ptr) {
-  ptr->AddRef();
-}
-
-template <typename T>
-void scoped_refptr<T>::Release(T* ptr) {
-  ptr->Release();
-}
-
-// Handy utility for creating a scoped_refptr<T> out of a T* explicitly without
-// having to retype all the template arguments
-template <typename T>
-scoped_refptr<T> make_scoped_refptr(T* t) {
-  return scoped_refptr<T>(t);
-}
-
-// Temporary operator overloads to facilitate the transition. See
-// https://crbug.com/110610.
-template <typename T, typename U>
-bool operator==(const scoped_refptr<T>& lhs, const U* rhs) {
-  return lhs.get() == rhs;
-}
-
-template <typename T, typename U>
-bool operator==(const T* lhs, const scoped_refptr<U>& rhs) {
-  return lhs == rhs.get();
-}
-
-template <typename T, typename U>
-bool operator!=(const scoped_refptr<T>& lhs, const U* rhs) {
-  return !operator==(lhs, rhs);
-}
-
-template <typename T, typename U>
-bool operator!=(const T* lhs, const scoped_refptr<U>& rhs) {
-  return !operator==(lhs, rhs);
-}
-
-template <typename T>
-std::ostream& operator<<(std::ostream& out, const scoped_refptr<T>& p) {
-  return out << p.get();
-}
-
-#endif  // BASE_MEMORY_REF_COUNTED_H_