image/FrozenImage.cpp
author Henri Sivonen <hsivonen@hsivonen.fi>
Fri, 06 Jul 2018 10:44:43 +0300
changeset 489140 4ef0f163fdeb9afeddd87b37bfd987298c038542
parent 458550 91d647c847e56cb0db2be19647507cec207b1d08
child 489182 69a4c2a0aac6e8bfc041a82b634611e1432af36b
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 http://mozilla.org/MPL/2.0/. */

#include "FrozenImage.h"

namespace mozilla {

using namespace gfx;
using layers::ImageContainer;
using layers::LayerManager;

namespace image {

void
FrozenImage::IncrementAnimationConsumers()
{
  // Do nothing. This will prevent animation from starting if there are no other
  // instances of this image.
}

void
FrozenImage::DecrementAnimationConsumers()
{
  // Do nothing.
}

NS_IMETHODIMP
FrozenImage::GetAnimated(bool* aAnimated)
{
  bool dummy;
  nsresult rv = InnerImage()->GetAnimated(&dummy);
  if (NS_SUCCEEDED(rv)) {
    *aAnimated = false;
  }
  return rv;
}

NS_IMETHODIMP_(already_AddRefed<SourceSurface>)
FrozenImage::GetFrame(uint32_t aWhichFrame,
                      uint32_t aFlags)
{
  return InnerImage()->GetFrame(FRAME_FIRST, aFlags);
}

NS_IMETHODIMP_(already_AddRefed<SourceSurface>)
FrozenImage::GetFrameAtSize(const IntSize& aSize,
                            uint32_t aWhichFrame,
                            uint32_t aFlags)
{
  return InnerImage()->GetFrameAtSize(aSize, FRAME_FIRST, aFlags);
}

NS_IMETHODIMP_(bool)
FrozenImage::IsImageContainerAvailable(LayerManager* aManager, uint32_t aFlags)
{
  return false;
}

NS_IMETHODIMP_(already_AddRefed<ImageContainer>)
FrozenImage::GetImageContainer(layers::LayerManager* aManager, uint32_t aFlags)
{
  // XXX(seth): GetImageContainer does not currently support anything but the
  // current frame. We work around this by always returning null, but if it ever
  // turns out that FrozenImage is widely used on codepaths that can actually
  // benefit from GetImageContainer, it would be a good idea to fix that method
  // for performance reasons.
  return nullptr;
}

NS_IMETHODIMP_(bool)
FrozenImage::IsImageContainerAvailableAtSize(LayerManager* aManager,
                                             const IntSize& aSize,
                                             uint32_t aFlags)
{
  return false;
}

NS_IMETHODIMP_(already_AddRefed<ImageContainer>)
FrozenImage::GetImageContainerAtSize(layers::LayerManager* aManager,
                                     const IntSize& aSize,
                                     const Maybe<SVGImageContext>& aSVGContext,
                                     uint32_t aFlags)
{
  // XXX(seth): GetImageContainer does not currently support anything but the
  // current frame. We work around this by always returning null, but if it ever
  // turns out that FrozenImage is widely used on codepaths that can actually
  // benefit from GetImageContainer, it would be a good idea to fix that method
  // for performance reasons.
  return nullptr;
}

NS_IMETHODIMP_(ImgDrawResult)
FrozenImage::Draw(gfxContext* aContext,
                  const nsIntSize& aSize,
                  const ImageRegion& aRegion,
                  uint32_t /* aWhichFrame - ignored */,
                  SamplingFilter aSamplingFilter,
                  const Maybe<SVGImageContext>& aSVGContext,
                  uint32_t aFlags,
                  float aOpacity)
{
  return InnerImage()->Draw(aContext, aSize, aRegion, FRAME_FIRST,
                            aSamplingFilter, aSVGContext, aFlags, aOpacity);
}

NS_IMETHODIMP_(void)
FrozenImage::RequestRefresh(const TimeStamp& aTime)
{
  // Do nothing.
}

NS_IMETHODIMP
FrozenImage::GetAnimationMode(uint16_t* aAnimationMode)
{
  *aAnimationMode = kNormalAnimMode;
  return NS_OK;
}

NS_IMETHODIMP
FrozenImage::SetAnimationMode(uint16_t aAnimationMode)
{
  // Do nothing.
  return NS_OK;
}

NS_IMETHODIMP
FrozenImage::ResetAnimation()
{
  // Do nothing.
  return NS_OK;
}

NS_IMETHODIMP_(float)
FrozenImage::GetFrameIndex(uint32_t aWhichFrame)
{
  MOZ_ASSERT(aWhichFrame <= FRAME_MAX_VALUE, "Invalid argument");
  return 0;
}

} // namespace image
} // namespace mozilla