cc/base/ref_counted_managed.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CC_BASE_REF_COUNTED_MANAGED_H_
   6 #define CC_BASE_REF_COUNTED_MANAGED_H_
   7
   8 #include "base/logging.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "cc/base/cc_export.h"
  11
  12 namespace cc {
  13
  14 template <typename T> class RefCountedManaged;
  15
  16 template <typename T>
  17 class CC_EXPORT RefCountedManager {
  18  protected:
  19   RefCountedManager() : live_object_count_(0) {}
  20   ~RefCountedManager() {
  21     CHECK_EQ(0, live_object_count_);
  22   }
  23
  24   virtual void Release(T* object) = 0;
  25
  26  private:
  27   friend class RefCountedManaged<T>;
  28   int live_object_count_;
  29 };
  30
  31 template <typename T>
  32 class CC_EXPORT RefCountedManaged : public base::subtle::RefCountedBase {
  33  public:
  34   explicit RefCountedManaged(RefCountedManager<T>* manager)
  35       : manager_(manager) {
  36     manager_->live_object_count_++;
  37   }
  38
  39   void AddRef() const {
  40     base::subtle::RefCountedBase::AddRef();
  41   }
  42
  43   void Release() {
  44     if (base::subtle::RefCountedBase::Release()) {
  45       DCHECK_GT(manager_->live_object_count_, 0);
  46       manager_->live_object_count_--;
  47
  48       // This must be the last statement in case manager deletes
  49       // the object immediately.
  50       manager_->Release(static_cast<T*>(this));
  51     }
  52   }
  53
  54  protected:
  55   ~RefCountedManaged() {}
  56
  57  private:
  58   RefCountedManager<T>* manager_;
  59
  60   DISALLOW_COPY_AND_ASSIGN(RefCountedManaged<T>);
  61 };
  62
  63 }  // namespace cc
  64
  65 #endif  // CC_BASE_REF_COUNTED_MANAGED_H_