The Tor Browser: dom/smil/nsSMILTimeContainer.h@97036ab72558 (annotated)

dom/smil/nsSMILTimeContainer.h@97036ab72558 (annotated)

dom/smil/nsSMILTimeContainer.h

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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 NS_SMILTIMECONTAINER_H_
 #define NS_SMILTIMECONTAINER_H_
 #include "mozilla/dom/SVGAnimationElement.h"
 #include "nscore.h"
 #include "nsSMILTypes.h"
 #include "nsTPriorityQueue.h"
 #include "nsAutoPtr.h"
 #include "nsSMILMilestone.h"
 class nsSMILTimeValue;
 //----------------------------------------------------------------------
 // nsSMILTimeContainer
 //
 // Common base class for a time base that can be paused, resumed, and sampled.
 //
 class nsSMILTimeContainer
 {
 public:
   nsSMILTimeContainer();
   virtual ~nsSMILTimeContainer();
   /*
    * Pause request types.
    */
   enum {
     PAUSE_BEGIN    =  1, // Paused because timeline has yet to begin.
     PAUSE_SCRIPT   =  2, // Paused by script.
     PAUSE_PAGEHIDE =  4, // Paused because our doc is hidden.
     PAUSE_USERPREF =  8, // Paused because animations are disabled in prefs.
     PAUSE_IMAGE    = 16  // Paused becuase we're in an image that's suspended.
   };
   /*
    * Cause the time container to record its begin time.
    */
   void Begin();
   /*
    * Pause this time container
    *
    * @param aType The source of the pause request. Successive calls to Pause
    * with the same aType will be ignored. The container will remain paused until
    * each call to Pause of a given aType has been matched by at least one call
    * to Resume with the same aType.
    */
   virtual void Pause(uint32_t aType);
   /*
    * Resume this time container
    *
    * param @aType The source of the resume request. Clears the pause flag for
    * this particular type of pause request. When all pause flags have been
    * cleared the time container will be resumed.
    */
   virtual void Resume(uint32_t aType);
   /**
    * Returns true if this time container is paused by the specified type.
    * Note that the time container may also be paused by other types; this method
    * does not test if aType is the exclusive pause source.
    *
    * @param @aType The pause source to test for.
    * @return true if this container is paused by aType.
    */
   bool IsPausedByType(uint32_t aType) const { return mPauseState & aType; }
   /**
    * Returns true if this time container is paused.
    * Generally you should test for a specific type of pausing using
    * IsPausedByType.
    *
    * @return true if this container is paused, false otherwise.
    */
   bool IsPaused() const { return mPauseState != 0; }
   /*
    * Return the time elapsed since this time container's begin time (expressed
    * in parent time) minus any accumulated offset from pausing.
    */
   nsSMILTime GetCurrentTime() const;
   /*
    * Seek the document timeline to the specified time.
    *
    * @param aSeekTo The time to seek to, expressed in this time container's time
    * base (i.e. the same units as GetCurrentTime).
    */
   void SetCurrentTime(nsSMILTime aSeekTo);
   /*
    * Return the current time for the parent time container if any.
    */
   virtual nsSMILTime GetParentTime() const;
   /*
    * Convert container time to parent time.
    *
    * @param   aContainerTime The container time to convert.
    * @return  The equivalent parent time or indefinite if the container is
    *          paused and the time is in the future.
    */
   nsSMILTimeValue ContainerToParentTime(nsSMILTime aContainerTime) const;
   /*
    * Convert from parent time to container time.
    *
    * @param   aParentTime The parent time to convert.
    * @return  The equivalent container time or indefinite if the container is
    *          paused and aParentTime is after the time when the pause began.
    */
   nsSMILTimeValue ParentToContainerTime(nsSMILTime aParentTime) const;
   /*
    * If the container is paused, causes the pause time to be updated to the
    * current parent time. This should be called before updating
    * cross-container dependencies that will call ContainerToParentTime in order
    * to provide more intuitive results.
    */
   void SyncPauseTime();
   /*
    * Updates the current time of this time container and calls DoSample to
    * perform any sample-operations.
    */
   void Sample();
   /*
    * Return if this time container should be sampled or can be skipped.
    *
    * This is most useful as an optimisation for skipping time containers that
    * don't require a sample.
    */
   bool NeedsSample() const { return !mPauseState || mNeedsPauseSample; }
   /*
    * Indicates if the elements of this time container need to be rewound.
    * This occurs during a backwards seek.
    */
   bool NeedsRewind() const { return mNeedsRewind; }
   void ClearNeedsRewind() { mNeedsRewind = false; }
   /*
    * Indicates the time container is currently processing a SetCurrentTime
    * request and appropriate seek behaviour should be applied by child elements
    * (e.g. not firing time events).
    */
   bool IsSeeking() const { return mIsSeeking; }
   void MarkSeekFinished() { mIsSeeking = false; }
   /*
    * Sets the parent time container.
    *
    * The callee still retains ownership of the time container.
    */
   nsresult SetParent(nsSMILTimeContainer* aParent);
   /*
    * Registers an element for a sample at the given time.
    *
    * @param   aMilestone  The milestone to register in container time.
    * @param   aElement    The timebase element that needs a sample at
    *                      aMilestone.
    * @return  true if the element was successfully added, false otherwise.
    */
   bool AddMilestone(const nsSMILMilestone& aMilestone,
                     mozilla::dom::SVGAnimationElement& aElement);
   /*
    * Resets the list of milestones.
    */
   void ClearMilestones();
   /*
    * Returns the next significant transition from amongst the registered
    * milestones.
    *
    * @param[out] aNextMilestone The next milestone with time in parent time.
    *
    * @return true if there exists another milestone, false otherwise in
    * which case aNextMilestone will be unmodified.
    */
   bool GetNextMilestoneInParentTime(nsSMILMilestone& aNextMilestone) const;
   typedef nsTArray<nsRefPtr<mozilla::dom::SVGAnimationElement> > AnimElemArray;
   /*
    * Removes and returns the timebase elements from the start of the list of
    * timebase elements that match the given time.
    *
    * @param      aMilestone  The milestone time to match in parent time. This
    *                         must be <= GetNextMilestoneInParentTime.
    * @param[out] aMatchedElements The array to which matching elements will be
    *                              appended.
    * @return true if one or more elements match, false otherwise.
    */
   bool PopMilestoneElementsAtMilestone(const nsSMILMilestone& aMilestone,
                                          AnimElemArray& aMatchedElements);
   // Cycle-collection support
   void Traverse(nsCycleCollectionTraversalCallback* aCallback);
   void Unlink();
 protected:
   /*
    * Per-sample operations to be performed whenever Sample() is called and
    * NeedsSample() is true. Called after updating mCurrentTime;
    */
   virtual void DoSample() { }
   /*
    * Adding and removing child containers is not implemented in the base class
    * because not all subclasses need this.
    */
   /*
    * Adds a child time container.
    */
   virtual nsresult AddChild(nsSMILTimeContainer& aChild)
   {
     return NS_ERROR_FAILURE;
   }
   /*
    * Removes a child time container.
    */
   virtual void RemoveChild(nsSMILTimeContainer& aChild) { }
   /*
    * Implementation helper to update the current time.
    */
   void UpdateCurrentTime();
   /*
    * Implementation helper to notify timed elements with dependencies that the
    * container time has changed with respect to the document time.
    */
   void NotifyTimeChange();
   // The parent time container, if any
   nsSMILTimeContainer* mParent;
   // The current time established at the last call to Sample()
   nsSMILTime mCurrentTime;
   // The number of milliseconds for which the container has been paused
   // (excluding the current pause interval if the container is currently
   // paused).
   //
   //  Current time = parent time - mParentOffset
   //
   nsSMILTime mParentOffset;
   // The timestamp in parent time when the container was paused
   nsSMILTime mPauseStart;
   // Whether or not a pause sample is required
   bool mNeedsPauseSample;
   bool mNeedsRewind; // Backwards seek performed
   bool mIsSeeking; // Currently in the middle of a seek operation
   // A bitfield of the pause state for all pause requests
   uint32_t mPauseState;
   struct MilestoneEntry
   {
     MilestoneEntry(nsSMILMilestone aMilestone,
                    mozilla::dom::SVGAnimationElement& aElement)
       : mMilestone(aMilestone), mTimebase(&aElement)
     { }
     bool operator<(const MilestoneEntry& aOther) const
     {
       return mMilestone < aOther.mMilestone;
     }
     nsSMILMilestone mMilestone; // In container time.
     nsRefPtr<mozilla::dom::SVGAnimationElement> mTimebase;
   };
   // Queue of elements with registered milestones. Used to update the model with
   // significant transitions that occur between two samples. Since timed element
   // re-register their milestones when they're sampled this is reset once we've
   // taken care of the milestones before the current sample time but before we
   // actually do the full sample.
   nsTPriorityQueue<MilestoneEntry> mMilestoneEntries;
 };
 #endif // NS_SMILTIMECONTAINER_H_

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dom/smil/nsSMILTimeContainer.h@97036ab72558 (annotated)

dom/smil/nsSMILTimeContainer.h