cefpython/src/include/base/cef_ref_counted.h at cefpython53 · llcc01/cefpython

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// Copyright (c) 2014 Marshall A. Greenblatt. Portions copyright (c) 2012
// Google Inc. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
//    * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//    * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//    * Neither the name of Google Inc. nor the name Chromium Embedded
// Framework nor the names of its contributors may be used to endorse
// or promote products derived from this software without specific prior
// written permission.
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef CEF_INCLUDE_BASE_CEF_REF_COUNTED_H_
#define CEF_INCLUDE_BASE_CEF_REF_COUNTED_H_
#pragma once
#if defined(BASE_MEMORY_REF_COUNTED_H_)
// Do nothing if the Chromium header has already been included.
// This can happen in cases where Chromium code is used directly by the
// client application. When using Chromium code directly always include
// the Chromium header first to avoid type conflicts.
#elif defined(USING_CHROMIUM_INCLUDES)
// When building CEF include the Chromium header directly.
#include "base/memory/ref_counted.h"
#else  // !USING_CHROMIUM_INCLUDES
// The following is substantially similar to the Chromium implementation.
// If the Chromium implementation diverges the below implementation should be
// updated to match.
#include <cassert>
#include "include/base/cef_atomic_ref_count.h"
#include "include/base/cef_build.h"
#include "include/base/cef_logging.h"
#include "include/base/cef_thread_collision_warner.h"
namespace base {
namespace cef_subtle {
class RefCountedBase {
  bool HasOneRef() const { return ref_count_ == 1; }
 protected:
  RefCountedBase()
      : ref_count_(0)
  #if DCHECK_IS_ON()
      , in_dtor_(false)
  ~RefCountedBase() {
  #if DCHECK_IS_ON()
    DCHECK(in_dtor_) << "RefCounted object deleted without calling Release()";
  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_);
  #if DCHECK_IS_ON()
    DCHECK(!in_dtor_);
    ++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_);
  #if DCHECK_IS_ON()
    DCHECK(!in_dtor_);
    if (--ref_count_ == 0) {
  #if DCHECK_IS_ON()
      in_dtor_ = true;
      return true;
    return false;
  mutable int ref_count_;
#if DCHECK_IS_ON()
  mutable bool in_dtor_;
  DFAKE_MUTEX(add_release_);
  DISALLOW_COPY_AND_ASSIGN(RefCountedBase);
class RefCountedThreadSafeBase {
  bool HasOneRef() const;
 protected:
  RefCountedThreadSafeBase();
  ~RefCountedThreadSafeBase();
  void AddRef() const;
  // Returns true if the object should self-delete.
  bool Release() const;
  mutable AtomicRefCount ref_count_;
#if DCHECK_IS_ON()
  mutable bool in_dtor_;
  DISALLOW_COPY_AND_ASSIGN(RefCountedThreadSafeBase);
}  // namespace cef_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 cef_subtle::RefCountedBase {
  RefCounted() {}
  void AddRef() const {
    cef_subtle::RefCountedBase::AddRef();
  void Release() const {
    if (cef_subtle::RefCountedBase::Release()) {
      delete static_cast<const T*>(this);
 protected:
  ~RefCounted() {}
  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 cef_subtle::RefCountedThreadSafeBase {
  RefCountedThreadSafe() {}
  void AddRef() const {
    cef_subtle::RefCountedThreadSafeBase::AddRef();
  void Release() const {
    if (cef_subtle::RefCountedThreadSafeBase::Release()) {
      Traits::Destruct(static_cast<const T*>(this));
 protected:
  ~RefCountedThreadSafe() {}
  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> > {
  RefCountedData() : data() {}
  RefCountedData(const T& in_value) : data(in_value) {}
  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 {
  typedef T element_type;
  scoped_refptr() : ptr_(NULL) {
  scoped_refptr(T* p) : ptr_(p) {
    if (ptr_)
      ptr_->AddRef();
  scoped_refptr(const scoped_refptr<T>& r) : ptr_(r.ptr_) {
    if (ptr_)
      ptr_->AddRef();
  template <typename U>
  scoped_refptr(const scoped_refptr<U>& r) : ptr_(r.get()) {
    if (ptr_)
      ptr_->AddRef();
  ~scoped_refptr() {
    if (ptr_)
      ptr_->Release();
  T* get() const { return ptr_; }
  // Allow scoped_refptr<C> to be used in boolean expression
  // and comparison operations.
  operator T*() const { return ptr_; }
  T* operator->() const {
    assert(ptr_ != NULL);
    return ptr_;
  scoped_refptr<T>& operator=(T* p) {
    // AddRef first so that self assignment should work
      p->AddRef();
    T* old_ptr = ptr_;
    ptr_ = p;
    if (old_ptr)
      old_ptr->Release();
    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();
  void swap(T** pp) {
    T* p = ptr_;
    ptr_ = *pp;
    *pp = p;
  void swap(scoped_refptr<T>& r) {
    swap(&r.ptr_);
 protected:
// 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);
#endif  // !USING_CHROMIUM_INCLUDES
#endif  // CEF_INCLUDE_BASE_CEF_REF_COUNTED_H_
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