DDLifetime.h - mozsearch

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim:set ts=2 sw=2 sts=2 et cindent: */

/* 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 DDLifetime_h_

#define DDLifetime_h_

#include "DDLogObject.h"

#include "DDMessageIndex.h"

#include "DDTimeStamp.h"

namespace mozilla {

namespace dom {

class HTMLMediaElement;

}  // namespace dom

// This struct records the lifetime of one C++ object.

// Note that multiple objects may have the same address and type (at different

// times), so the recorded construction/destruction times should be used to

// distinguish them.

struct DDLifetime {

  const DDLogObject mObject;

  const DDMessageIndex mConstructionIndex;

  const DDTimeStamp mConstructionTimeStamp;

  // Only valid when mDestructionTimeStamp is not null.

  DDMessageIndex mDestructionIndex;

  DDTimeStamp mDestructionTimeStamp;

  // Associated HTMLMediaElement, initially nullptr until this object can be

  // linked to its HTMLMediaElement.

  const dom::HTMLMediaElement* mMediaElement;

  // If not null, derived object for which this DDLifetime is a base class.

  // This is used to link messages from the same object, even when they

  // originate from a method on a base class.

  // Note: We assume a single-inheritance hierarchy.

  DDLogObject mDerivedObject;

  DDMessageIndex mDerivedObjectLinkingIndex;

  // Unique tag used to identify objects in a log, easier to read than object

  // pointers.

  // Negative and unique for unassociated objects.

  // Positive for associated objects, and unique for that HTMLMediaElement

  // group.

  int32_t mTag;

  DDLifetime(DDLogObject aObject, DDMessageIndex aConstructionIndex,

             DDTimeStamp aConstructionTimeStamp, int32_t aTag)

      : mObject(aObject),

        mConstructionIndex(aConstructionIndex),

        mConstructionTimeStamp(aConstructionTimeStamp),

        mDestructionIndex(0),

        mMediaElement(nullptr),

        mDerivedObjectLinkingIndex(0),

        mTag(aTag) {}

  // Is this lifetime alive at the given index?

  // I.e.: Constructed before, and destroyed later or not yet.

  bool IsAliveAt(DDMessageIndex aIndex) const {

    return aIndex >= mConstructionIndex &&

           (!mDestructionTimeStamp || aIndex <= mDestructionIndex);

  // Print the object's pointer, tag and class name (and derived class). E.g.:

  // "dom::HTMLVideoElement[134073800]#1 (as dom::HTMLMediaElement)"

  void AppendPrintf(nsCString& aString) const;

  nsCString Printf() const;

};

}  // namespace mozilla

#endif  // DDLifetime_h_