author Henri Sivonen <>
Fri, 06 Jul 2018 10:44:43 +0300
changeset 489140 4ef0f163fdeb9afeddd87b37bfd987298c038542
parent 477003 a7331d229cc8add978906ccc5582795bceb58d81
child 499553 8421b16c011ba49a2e495f81853b282413aa7650
permissions -rw-r--r--
Bug 1402247 - Use encoding_rs for XPCOM string encoding conversions. r=Nika,erahm,froydnj. Correctness improvements: * UTF errors are handled safely per spec instead of dangerously truncating strings. * There are fewer converter implementations. Performance improvements: * The old code did exact buffer length math, which meant doing UTF math twice on each input string (once for length calculation and another time for conversion). Exact length math is more complicated when handling errors properly, which the old code didn't do. The new code does UTF math on the string content only once (when converting) but risks allocating more than once. There are heuristics in place to lower the probability of reallocation in cases where the double math avoidance isn't enough of a saving to absorb an allocation and memcpy. * Previously, in UTF-16 <-> UTF-8 conversions, an ASCII prefix was optimized but a single non-ASCII code point pessimized the rest of the string. The new code tries to get back on the fast ASCII path. * UTF-16 to Latin1 conversion guarantees less about handling of out-of-range input to eliminate an operation from the inner loop on x86/x86_64. * When assigning to a pre-existing string, the new code tries to reuse the old buffer instead of first releasing the old buffer and then allocating a new one. * When reallocating from the new code, the memcpy covers only the data that is part of the logical length of the old string instead of memcpying the whole capacity. (For old callers old excess memcpy behavior is preserved due to bogus callers. See bug 1472113.) * UTF-8 strings in XPConnect that are in the Latin1 range are passed to SpiderMonkey as Latin1. New features: * Conversion between UTF-8 and Latin1 is added in order to enable faster future interop between Rust code (or otherwise UTF-8-using code) and text node and SpiderMonkey code that uses Latin1. MozReview-Commit-ID: JaJuExfILM9

/* -*- 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 */

#ifndef mozilla_image_FrameAnimator_h
#define mozilla_image_FrameAnimator_h

#include "mozilla/Maybe.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/TimeStamp.h"
#include "gfxTypes.h"
#include "imgFrame.h"
#include "nsCOMPtr.h"
#include "nsRect.h"
#include "SurfaceCache.h"
#include "gfxPrefs.h"

namespace mozilla {
namespace image {

class RasterImage;
class DrawableSurface;

class AnimationState
  explicit AnimationState(uint16_t aAnimationMode)
    : mFrameCount(0)
    , mCurrentAnimationFrameIndex(0)
    , mLoopRemainingCount(-1)
    , mLoopCount(-1)
    , mFirstFrameTimeout(FrameTimeout::FromRawMilliseconds(0))
    , mAnimationMode(aAnimationMode)
    , mHasBeenDecoded(false)
    , mHasRequestedDecode(false)
    , mIsCurrentlyDecoded(false)
    , mCompositedFrameInvalid(false)
    , mCompositedFrameRequested(false)
    , mDiscarded(false)
  { }

   * Call this whenever a decode completes, a decode starts, or the image is
   * discarded. It will update the internal state. Specifically mDiscarded,
   * mCompositedFrameInvalid, and mIsCurrentlyDecoded. If aAllowInvalidation
   * is true then returns a rect to invalidate.
  const gfx::IntRect UpdateState(bool aAnimationFinished,
                            RasterImage *aImage,
                            const gfx::IntSize& aSize,
                            bool aAllowInvalidation = true);
  const gfx::IntRect UpdateStateInternal(LookupResult& aResult,
                                    bool aAnimationFinished,
                                    const gfx::IntSize& aSize,
                                    bool aAllowInvalidation = true);

   * Call when a decode of this image has been completed.
  void NotifyDecodeComplete();

   * Returns true if this image has been fully decoded before.
  bool GetHasBeenDecoded() { return mHasBeenDecoded; }

   * Returns true if this image has ever requested a decode before.
  bool GetHasRequestedDecode() { return mHasRequestedDecode; }

   * Returns true if this image has been discarded and a decoded has not yet
   * been created to redecode it.
  bool IsDiscarded() { return mDiscarded; }

   * Sets the composited frame as valid or invalid.
  void SetCompositedFrameInvalid(bool aInvalid) {
    MOZ_ASSERT(!aInvalid || gfxPrefs::ImageMemAnimatedDiscardable());
    mCompositedFrameInvalid = aInvalid;

   * Returns whether the composited frame is valid to draw to the screen.
  bool GetCompositedFrameInvalid() {
    return mCompositedFrameInvalid;

   * Returns whether the image is currently full decoded..
  bool GetIsCurrentlyDecoded() {
    return mIsCurrentlyDecoded;

   * Call when you need to re-start animating. Ensures we start from the first
   * frame.
  void ResetAnimation();

   * The animation mode of the image.
   * Constants defined in imgIContainer.idl.
  void SetAnimationMode(uint16_t aAnimationMode);

  /// Update the number of frames of animation this image is known to have.
  void UpdateKnownFrameCount(uint32_t aFrameCount);

  /// @return the number of frames of animation we know about so far.
  uint32_t KnownFrameCount() const { return mFrameCount; }

  /// @return the number of frames this animation has, if we know for sure.
  /// (In other words, if decoding is finished.) Otherwise, returns Nothing().
  Maybe<uint32_t> FrameCount() const;

   * Get or set the area of the image to invalidate when we loop around to the
   * first frame.
  void SetFirstFrameRefreshArea(const gfx::IntRect& aRefreshArea);
  gfx::IntRect FirstFrameRefreshArea() const { return mFirstFrameRefreshArea; }

   * If the animation frame time has not yet been set, set it to
   * TimeStamp::Now().
  void InitAnimationFrameTimeIfNecessary();

   * Set the animation frame time to @aTime.
  void SetAnimationFrameTime(const TimeStamp& aTime);

   * Set the animation frame time to @aTime if we are configured to stop the
   * animation when not visible and aTime is later than the current time.
   * Returns true if the time was updated, else false.
  bool MaybeAdvanceAnimationFrameTime(const TimeStamp& aTime);

   * The current frame we're on, from 0 to (numFrames - 1).
  uint32_t GetCurrentAnimationFrameIndex() const;

   * Set number of times to loop the image.
   * @note -1 means loop forever.
  void SetLoopCount(int32_t aLoopCount) { mLoopCount = aLoopCount; }
  int32_t LoopCount() const { return mLoopCount; }

  /// Set the @aLength of a single loop through this image.
  void SetLoopLength(FrameTimeout aLength) { mLoopLength = Some(aLength); }

   * @return the length of a single loop of this image. If this image is not
   * finished decoding, is not animated, or it is animated but does not loop,
   * returns FrameTimeout::Forever().
  FrameTimeout LoopLength() const;

   * Get or set the timeout for the first frame. This is used to allow animation
   * scheduling even before a full decode runs for this image.
  void SetFirstFrameTimeout(FrameTimeout aTimeout) { mFirstFrameTimeout = aTimeout; }
  FrameTimeout FirstFrameTimeout() const { return mFirstFrameTimeout; }

  friend class FrameAnimator;

  //! Area of the first frame that needs to be redrawn on subsequent loops.
  gfx::IntRect mFirstFrameRefreshArea;

  //! the time that the animation advanced to the current frame
  TimeStamp mCurrentAnimationFrameTime;

  //! The number of frames of animation this image has.
  uint32_t mFrameCount;

  //! The current frame index we're on, in the range [0, mFrameCount).
  uint32_t mCurrentAnimationFrameIndex;

  //! number of loops remaining before animation stops (-1 no stop)
  int32_t mLoopRemainingCount;

  //! The total number of loops for the image.
  int32_t mLoopCount;

  //! The length of a single loop through this image.
  Maybe<FrameTimeout> mLoopLength;

  //! The timeout for the first frame of this image.
  FrameTimeout mFirstFrameTimeout;

  //! The animation mode of this image. Constants defined in imgIContainer.
  uint16_t mAnimationMode;

   * The following four bools (mHasBeenDecoded, mIsCurrentlyDecoded,
   * mCompositedFrameInvalid, mDiscarded) track the state of the image with
   * regards to decoding. They all start out false, including mDiscarded,
   * because we want to treat being discarded differently from "not yet decoded
   * for the first time".
   * (When we are decoding the image for the first time we want to show the
   * image at the speed of data coming in from the network or the speed
   * specified in the image file, whichever is slower. But when redecoding we
   * want to show nothing until the frame for the current time has been
   * decoded. The prevents the user from seeing the image "fast forward"
   * to the expected spot.)
   * When the image is decoded for the first time mHasBeenDecoded and
   * mIsCurrentlyDecoded get set to true. When the image is discarded
   * mIsCurrentlyDecoded gets set to false, and mCompositedFrameInvalid
   * & mDiscarded get set to true. When we create a decoder to redecode the
   * image mDiscarded gets set to false. mCompositedFrameInvalid gets set to
   * false when we are able to advance to the frame that should be showing
   * for the current time. mIsCurrentlyDecoded gets set to true when the
   * redecode finishes.

  //! Whether this image has been decoded at least once.
  bool mHasBeenDecoded;

  //! Whether this image has ever requested a decode.
  bool mHasRequestedDecode;

  //! Whether this image is currently fully decoded.
  bool mIsCurrentlyDecoded;

  //! Whether the composited frame is valid to draw to the screen, note that
  //! the composited frame can exist and be filled with image data but not
  //! valid to draw to the screen.
  bool mCompositedFrameInvalid;

  //! Whether the composited frame was requested from the animator since the
  //! last time we advanced the animation.
  bool mCompositedFrameRequested;

  //! Whether this image is currently discarded. Only set to true after the
  //! image has been decoded at least once.
  bool mDiscarded;

 * RefreshResult is used to let callers know how the state of the animation
 * changed during a call to FrameAnimator::RequestRefresh().
struct RefreshResult
    : mFrameAdvanced(false)
    , mAnimationFinished(false)
  { }

  /// Merges another RefreshResult's changes into this RefreshResult.
  void Accumulate(const RefreshResult& aOther)
    mFrameAdvanced = mFrameAdvanced || aOther.mFrameAdvanced;
    mAnimationFinished = mAnimationFinished || aOther.mAnimationFinished;
    mDirtyRect = mDirtyRect.Union(aOther.mDirtyRect);

  // The region of the image that has changed.
  gfx::IntRect mDirtyRect;

  // If true, we changed frames at least once. Note that, due to looping, we
  // could still have ended up on the same frame!
  bool mFrameAdvanced : 1;

  // Whether the animation has finished playing.
  bool mAnimationFinished : 1;

class FrameAnimator
  FrameAnimator(RasterImage* aImage, const gfx::IntSize& aSize)
    : mImage(aImage)
    , mSize(aSize)
    , mLastCompositedFrameIndex(-1)


   * Call when you need to re-start animating. Ensures we start from the first
   * frame.
  void ResetAnimation(AnimationState& aState);

   * Re-evaluate what frame we're supposed to be on, and do whatever blending
   * is necessary to get us to that frame.
   * Returns the result of that blending, including whether the current frame
   * changed and what the resulting dirty rectangle is.
  RefreshResult RequestRefresh(AnimationState& aState,
                               const TimeStamp& aTime,
                               bool aAnimationFinished);

   * Get the full frame for the current frame of the animation (it may or may
   * not have required compositing). It may not be available because it hasn't
   * been decoded yet, in which case we return an empty LookupResult.
  LookupResult GetCompositedFrame(AnimationState& aState);

   * Collect an accounting of the memory occupied by the compositing surfaces we
   * use during animation playback. All of the actual animation frames are
   * stored in the SurfaceCache, so we don't need to report them here.
  void CollectSizeOfCompositingSurfaces(nsTArray<SurfaceMemoryCounter>& aCounters,
                                        MallocSizeOf aMallocSizeOf) const;

private: // methods
   * Advances the animation. Typically, this will advance a single frame, but it
   * may advance multiple frames. This may happen if we have infrequently
   * "ticking" refresh drivers (e.g. in background tabs), or extremely short-
   * lived animation frames.
   * @param aTime the time that the animation should advance to. This will
   *              typically be <= TimeStamp::Now().
   * @param aCurrentFrame the currently displayed frame of the animation. If
   *                      we advance, it will replace aCurrentFrame with the
   *                      new current frame we advanced to.
   * @returns a RefreshResult that shows whether the frame was successfully
   *          advanced, and its resulting dirty rect.
  RefreshResult AdvanceFrame(AnimationState& aState,
                             DrawableSurface& aFrames,
                             RawAccessFrameRef& aCurrentFrame,
                             TimeStamp aTime);

   * Get the time the frame we're currently displaying is supposed to end.
   * In the error case (like if the requested frame is not currently
   * decoded), returns None().
  TimeStamp GetCurrentImgFrameEndTime(AnimationState& aState,
                                      FrameTimeout aCurrentTimeout) const;

  bool DoBlend(const RawAccessFrameRef& aPrevFrame,
               const RawAccessFrameRef& aNextFrame,
               uint32_t aNextFrameIndex,
               gfx::IntRect* aDirtyRect);

  /** Clears an area of <aFrame> with transparent black.
   * @param aFrameData Target Frame data
   * @param aFrameRect The rectangle of the data pointed ot by aFrameData
   * @note Does also clears the transparency mask
  static void ClearFrame(uint8_t* aFrameData, const gfx::IntRect& aFrameRect);

  //! @overload
  static void ClearFrame(uint8_t* aFrameData, const gfx::IntRect& aFrameRect,
                         const gfx::IntRect& aRectToClear);

  //! Copy one frame's image and mask into another
  static bool CopyFrameImage(const uint8_t* aDataSrc, const gfx::IntRect& aRectSrc,
                             uint8_t* aDataDest, const gfx::IntRect& aRectDest);

   * Draws one frame's image to into another, at the position specified by
   * aSrcRect.
   * @aSrcData the raw data of the current frame being drawn
   * @aSrcRect the size of the source frame, and the position of that frame in
   *           the composition frame
   * @aSrcPaletteLength the length (in bytes) of the palette at the beginning
   *                    of the source data (0 if image is not paletted)
   * @aSrcHasAlpha whether the source data represents an image with alpha
   * @aDstPixels the raw data of the composition frame where the current frame
   *             is drawn into (32-bit ARGB)
   * @aDstRect the size of the composition frame
   * @aBlendMethod the blend method for how to blend src on the composition
   * frame.
  static nsresult DrawFrameTo(const uint8_t* aSrcData,
                              const gfx::IntRect& aSrcRect,
                              uint32_t aSrcPaletteLength, bool aSrcHasAlpha,
                              uint8_t* aDstPixels, const gfx::IntRect& aDstRect,
                              BlendMethod aBlendMethod,
                              const gfx::IntRect& aBlendRect);

private: // data
  //! A weak pointer to our owning image.
  RasterImage* mImage;

  //! The intrinsic size of the image.
  gfx::IntSize mSize;

  /** For managing blending of frames
   * Some animations will use the compositingFrame to composite images
   * and just hand this back to the caller when it is time to draw the frame.
   * NOTE: When clearing compositingFrame, remember to set
   *       lastCompositedFrameIndex to -1.  Code assume that if
   *       lastCompositedFrameIndex >= 0 then compositingFrame exists.
  RawAccessFrameRef mCompositingFrame;

  /** the previous composited frame, for DISPOSE_RESTORE_PREVIOUS
   * The Previous Frame (all frames composited up to the current) needs to be
   * stored in cases where the image specifies it wants the last frame back
   * when it's done with the current frame.
  RawAccessFrameRef mCompositingPrevFrame;

  //! Track the last composited frame for Optimizations (See DoComposite code)
  int32_t mLastCompositedFrameIndex;

} // namespace image
} // namespace mozilla

#endif // mozilla_image_FrameAnimator_h