gecko-dev/gfx/layers/AtomicRefCountedWithFinalize.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef MOZILLA_ATOMICREFCOUNTEDWITHFINALIZE_H_
#define MOZILLA_ATOMICREFCOUNTEDWITHFINALIZE_H_

#include "mozilla/RefPtr.h"
#include "mozilla/Likely.h"
#include "MainThreadUtils.h"
#include "base/message_loop.h"
#include "base/task.h"
#include "mozilla/gfx/Logging.h"

#define ADDREF_MANUALLY(obj) \
  (obj)->AddRefManually(__FUNCTION__, __FILE__, __LINE__)
#define RELEASE_MANUALLY(obj) \
  (obj)->ReleaseManually(__FUNCTION__, __FILE__, __LINE__)

namespace mozilla {

template <class U>
class StaticRefPtr;

namespace gl {
template <typename T>
class RefSet;

template <typename T>
class RefQueue;
}  // namespace gl

template <typename T>
class AtomicRefCountedWithFinalize {
 protected:
  explicit AtomicRefCountedWithFinalize(const char* aName)
      : mRecycleCallback(nullptr),
        mClosure(nullptr),
        mRefCount(0)
#ifdef DEBUG
        ,
        mSpew(false),
        mManualAddRefs(0),
        mManualReleases(0)
#endif
#ifdef NS_BUILD_REFCNT_LOGGING
        ,
        mName(aName)
#endif
  {
  }

  ~AtomicRefCountedWithFinalize() {
    if (mRefCount >= 0) {
      gfxCriticalError() << "Deleting referenced object? " << mRefCount;
    }
  }

 public:
  // Mark user classes that are considered flawless.
  template <class U>
  friend class ::mozilla::StaticRefPtr;

  template <class U>
  friend struct mozilla::RefPtrTraits;

  template <typename U>
  friend class ::mozilla::gl::RefSet;

  template <typename U>
  friend class ::mozilla::gl::RefQueue;

  // friend class mozilla::gl::SurfaceFactory;

  void AddRefManually(const char* funcName, const char* fileName,
                      uint32_t lineNum) {
#ifdef DEBUG
    uint32_t count = ++mManualAddRefs;
    if (mSpew) {
      printf_stderr("AddRefManually() #%u in %s at %s:%u\n", count, funcName,
                    fileName, lineNum);
    }
#else
    (void)funcName;
    (void)fileName;
    (void)lineNum;
#endif
    AddRef();
  }

  void ReleaseManually(const char* funcName, const char* fileName,
                       uint32_t lineNum) {
#ifdef DEBUG
    uint32_t count = ++mManualReleases;
    if (mSpew) {
      printf_stderr("ReleaseManually() #%u in %s at %s:%u\n", count, funcName,
                    fileName, lineNum);
    }
#else
    (void)funcName;
    (void)fileName;
    (void)lineNum;
#endif
    Release();
  }

 private:
  void AddRef() {
    MOZ_ASSERT(mRefCount >= 0, "AddRef() during/after Finalize()/dtor.");
#ifdef NS_BUILD_REFCNT_LOGGING
    int currCount = ++mRefCount;
    NS_LOG_ADDREF(this, currCount, mName, sizeof(*this));
#else
    ++mRefCount;
#endif
  }

  void Release() {
    MOZ_ASSERT(mRefCount > 0, "Release() during/after Finalize()/dtor.");
    // Read mRecycleCallback early so that it does not get set to
    // deleted memory, if the object is goes away.  See bug 994903.
    // This saves us in the case where there is no callback, so that
    // we can do the "else if" below.
    RecycleCallback recycleCallback = mRecycleCallback;
    int currCount = --mRefCount;
    if (currCount < 0) {
      gfxCriticalError() << "Invalid reference count release" << currCount;
      ++mRefCount;
      return;
    }
#ifdef NS_BUILD_REFCNT_LOGGING
    NS_LOG_RELEASE(this, currCount, mName);
#endif

    if (0 == currCount) {
      mRefCount = detail::DEAD;
      MOZ_ASSERT(IsDead());

      // Recycle listeners must call ClearRecycleCallback
      // before releasing their strong reference.
      if (mRecycleCallback) {
        gfxCriticalError() << "About to release with valid callback";
        mRecycleCallback = nullptr;
      }

      MOZ_ASSERT(mManualAddRefs == mManualReleases);

      T* derived = static_cast<T*>(this);
      derived->Finalize();
      delete derived;
    } else if (1 == currCount && recycleCallback) {
      // There is nothing enforcing this in the code, except how the callers
      // are being careful to never let the reference count go down if there
      // is a callback.
      MOZ_ASSERT(!IsDead());
      T* derived = static_cast<T*>(this);
      recycleCallback(derived, mClosure);
    }
  }

 public:
  typedef void (*RecycleCallback)(T* aObject, void* aClosure);
  /**
   * Set a callback responsible for recycling this object
   * before it is finalized.
   */
  void SetRecycleCallback(RecycleCallback aCallback, void* aClosure) {
    MOZ_ASSERT(!IsDead());
    mRecycleCallback = aCallback;
    mClosure = aClosure;
  }
  void ClearRecycleCallback() {
    MOZ_ASSERT(!IsDead());
    SetRecycleCallback(nullptr, nullptr);
  }

  bool HasRecycleCallback() const {
    MOZ_ASSERT(!IsDead());
    return !!mRecycleCallback;
  }

  bool IsDead() const { return mRefCount < 0; }

  bool HasOneRef() const { return mRefCount == 1; }

 private:
  RecycleCallback mRecycleCallback;
  void* mClosure;
  Atomic<int> mRefCount;
#ifdef DEBUG
 public:
  bool mSpew;

 private:
  Atomic<uint32_t> mManualAddRefs;
  Atomic<uint32_t> mManualReleases;
#endif
#ifdef NS_BUILD_REFCNT_LOGGING
  const char* mName;
#endif
};

}  // namespace mozilla

#endif