/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Mozilla SMIL module.
 *
 * The Initial Developer of the Original Code is Brian Birtles.
 * Portions created by the Initial Developer are Copyright (C) 2005
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Brian Birtles <birtles@gmail.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef NS_SMILINSTANCETIME_H_
#define NS_SMILINSTANCETIME_H_

#include "nsSMILTimeValue.h"
#include "nsAutoPtr.h"

class nsSMILTimeValueSpec;

//----------------------------------------------------------------------
// nsSMILInstanceTime
//
// An instant in document simple time that may be used in creating a new
// interval.
//
// For an overview of how this class is related to other SMIL time classes see
// the documentation in nsSMILTimeValue.h
//
// These objects are owned by an nsSMILTimedElement but may be referred to by
// nsSMILTimeValueSpec objects owned by the same nsSMILTimedElement.
//
// For example, a syncbase nsSMILTimeValueSpec such as 'a.begin' will generate
// instance times based on when 'a' begins and will give these instance times to
// the owner nsSMILTimedElement. It will also keep a pointer to the last created
// instance time so it can tell its owner nsSMILTimedElement to update or
// delete it.
//
// Furthermore, nsSMILInstanceTime objects may refer to other nsSMILInstanceTime
// objects to represent dependency chains that are used for resolving priorities
// within the animation sandwich.

class nsSMILInstanceTime
{
public:
  // Instance time source. Times generated by events, syncbase relationships,
  // and DOM calls behave differently in some circumstances such as when a timed
  // element is reset.
  enum nsSMILInstanceTimeSource {
    // No particularly significant source, e.g. offset time, 'indefinite'
    SOURCE_NONE,
    // Generated by a DOM call such as beginElement
    SOURCE_DOM,
    // Generated by a syncbase relationship
    SOURCE_SYNCBASE,
    // Generated by an event
    SOURCE_EVENT
  };

  nsSMILInstanceTime(const nsSMILTimeValue& aTime,
                     const nsSMILInstanceTime* aDependentTime,
                     nsSMILInstanceTimeSource aSource = SOURCE_NONE);

  const nsSMILTimeValue& Time() const { return mTime; }

  const nsSMILInstanceTime* GetDependentTime() const { return mDependentTime; }
  void SetDependentTime(const nsSMILInstanceTime* aDependentTime);

  PRBool ClearOnReset() const { return !!(mFlags & kClearOnReset); }
  PRBool MayUpdate() const { return !!(mFlags & kMayUpdate); }
  PRBool FromDOM() const { return !!(mFlags & kFromDOM); }

  void MarkNoLongerUpdating()
  {
    mFlags &= ~kMayUpdate;
  }

  void DependentUpdate(const nsSMILTimeValue& aNewTime)
  {
    NS_ABORT_IF_FALSE(MayUpdate(),
        "Updating an instance time that is not expected to be updated");
    mTime = aNewTime;
  }

  PRBool IsDependent(const nsSMILInstanceTime& aOther,
                     PRUint32 aRecursionDepth = 0) const;

  PRBool SameTimeAndDependency(const nsSMILInstanceTime& aOther) const
  {
    return mTime == aOther.mTime && mDependentTime == aOther.mDependentTime;
  }

  // Get and set a serial number which may be used by a containing class to
  // control the sort order of otherwise similar instance times.
  PRUint32 Serial() const { return mSerial; }
  void SetSerial(PRUint32 aIndex) { mSerial = aIndex; }

  nsrefcnt AddRef()
  {
    if (mRefCnt == PR_UINT32_MAX) {
      NS_WARNING("refcount overflow, leaking nsSMILInstanceTime");
      return mRefCnt;
    }
    NS_ASSERT_OWNINGTHREAD(_class);
    NS_ABORT_IF_FALSE(_mOwningThread.GetThread() == PR_GetCurrentThread(),
        "nsSMILInstanceTime addref isn't thread-safe!");
    ++mRefCnt;
    NS_LOG_ADDREF(this, mRefCnt, "nsSMILInstanceTime", sizeof(*this));
    return mRefCnt;
  }

  nsrefcnt Release()
  {
    if (mRefCnt == PR_UINT32_MAX) {
      NS_WARNING("refcount overflow, leaking nsSMILInstanceTime");
      return mRefCnt;
    }
    NS_ABORT_IF_FALSE(_mOwningThread.GetThread() == PR_GetCurrentThread(),
        "nsSMILInstanceTime release isn't thread-safe!");
    --mRefCnt;
    NS_LOG_RELEASE(this, mRefCnt, "nsSMILInstanceTime");
    if (mRefCnt == 0) {
      delete this;
      return 0;
    }
    return mRefCnt;
  }

protected:
  void BreakPotentialCycle(const nsSMILInstanceTime* aNewTail);

  nsSMILTimeValue mTime;

  nsAutoRefCnt mRefCnt;
  NS_DECL_OWNINGTHREAD

  // Internal flags used for represent behaviour of different instance times`
  enum {
    // Indicates if this instance time should be removed when the owning timed
    // element is reset. True for events and DOM calls.
    kClearOnReset = 1,

    // Indicates that this instance time is referred to by an
    // nsSMILTimeValueSpec and as such may be updated. Such instance time should
    // not be filtered out by the nsSMILTimedElement even if they appear to be
    // in the past as they may be updated to a future time. Initially set for
    // syncbase-generated times until they are frozen.
    kMayUpdate = 2,

    // Indicates that this instance time was generated from the DOM as opposed
    // to an nsSMILTimeValueSpec. When a 'begin' or 'end' attribute is set or
    // reset we should clear all the instance times that have been generated by
    // that attribute (and hence an nsSMILTimeValueSpec), but not those from the
    // DOM.
    kFromDOM = 4
  };
  PRUint8  mFlags; // Combination of kClearOnReset, kMayUpdate, etc.
  PRUint32 mSerial; // A serial number used by the containing class to specify
                    // the sort order for instance times with the same mTime.

  // The instance time upon which this instance time is based (if any). This is
  // ONLY used for determining the compositing order of animations.
  nsRefPtr<nsSMILInstanceTime> mDependentTime;
};

#endif // NS_SMILINSTANCETIME_H_