Create 2272 release branch for CEF3.

git-svn-id: https://chromiumembedded.googlecode.com/svn/branches/2272@1993 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

include/base/cef_ref_counted.h

@@ -0,0 +1,386 @@
+// 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
+// met:
+//
+//    * 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(BUILDING_CEF_SHARED)
+// When building CEF include the Chromium header directly.
+#include "base/memory/ref_counted.h"
+#else  // !BUILDING_CEF_SHARED
+// 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"
+#ifndef NDEBUG
+#include "include/base/cef_logging.h"
+#endif
+#include "include/base/cef_thread_collision_warner.h"
+
+namespace base {
+
+namespace subtle {
+
+class 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 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 {
+ public:
+  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
+    if (p)
+      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:
+  T* ptr_;
+};
+
+// 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  // !BUILDING_CEF_SHARED
+
+#endif  // CEF_INCLUDE_BASE_CEF_REF_COUNTED_H_