image/DecodedSurfaceProvider.cpp
author Axel Hecht <axel@pike.org>
Mon, 05 Jun 2017 10:28:33 +0200
changeset 411345 91ddd067412484aec8d482eabe27eb048bea7ef8
parent 378860 4a3433f44ccf676a20c3083ee5fef686951d120c
child 428468 85cdb40c26211ea3288c46927641e14f0f5661d9
permissions -rw-r--r--
bug 1370176, generic configuration for l10n, r=flod,gps The current way to configure compare-locales has a lot of assumptions that make our l10n system really stubborn. The generic configuration is independent of python, and uses toml files for configuration. They're still modular, but there's only one file format. See http://moz-l10n-config.readthedocs.io/en/latest/fileformat.html for the specification. Also fixes a few nits in filter.py, where we compared the entity key as bool, which is false if we pass in ''. Explicitly compare as "entity is None" to be precise about when we're checking files. MozReview-Commit-ID: 5TmfobaImF4

/* -*- 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 "DecodedSurfaceProvider.h"

#include "gfxPrefs.h"
#include "nsProxyRelease.h"

#include "Decoder.h"

using namespace mozilla::gfx;

namespace mozilla {
namespace image {

DecodedSurfaceProvider::DecodedSurfaceProvider(NotNull<RasterImage*> aImage,
                                               const SurfaceKey& aSurfaceKey,
                                               NotNull<Decoder*> aDecoder)
  : ISurfaceProvider(ImageKey(aImage.get()), aSurfaceKey,
                     AvailabilityState::StartAsPlaceholder())
  , mImage(aImage.get())
  , mMutex("mozilla::image::DecodedSurfaceProvider")
  , mDecoder(aDecoder.get())
{
  MOZ_ASSERT(!mDecoder->IsMetadataDecode(),
             "Use MetadataDecodingTask for metadata decodes");
  MOZ_ASSERT(mDecoder->IsFirstFrameDecode(),
             "Use AnimationSurfaceProvider for animation decodes");
}

DecodedSurfaceProvider::~DecodedSurfaceProvider()
{
  DropImageReference();
}

void
DecodedSurfaceProvider::DropImageReference()
{
  if (!mImage) {
    return;  // Nothing to do.
  }

  // RasterImage objects need to be destroyed on the main thread. We also need
  // to destroy them asynchronously, because if our surface cache entry is
  // destroyed and we were the only thing keeping |mImage| alive, RasterImage's
  // destructor may call into the surface cache while whatever code caused us to
  // get evicted is holding the surface cache lock, causing deadlock.
  RefPtr<RasterImage> image = mImage;
  mImage = nullptr;
  NS_ReleaseOnMainThreadSystemGroup(image.forget(), /* aAlwaysProxy = */ true);
}

DrawableFrameRef
DecodedSurfaceProvider::DrawableRef(size_t aFrame)
{
  MOZ_ASSERT(aFrame == 0,
             "Requesting an animation frame from a DecodedSurfaceProvider?");

  // We depend on SurfaceCache::SurfaceAvailable() to provide synchronization
  // for methods that touch |mSurface|; after SurfaceAvailable() is called,
  // |mSurface| should be non-null and shouldn't be mutated further until we get
  // destroyed. That means that the assertions below are very important; we'll
  // end up with data races if these assumptions are violated.
  if (Availability().IsPlaceholder()) {
    MOZ_ASSERT_UNREACHABLE("Calling DrawableRef() on a placeholder");
    return DrawableFrameRef();
  }

  if (!mSurface) {
    MOZ_ASSERT_UNREACHABLE("Calling DrawableRef() when we have no surface");
    return DrawableFrameRef();
  }

  return mSurface->DrawableRef();
}

bool
DecodedSurfaceProvider::IsFinished() const
{
  // See DrawableRef() for commentary on these assertions.
  if (Availability().IsPlaceholder()) {
    MOZ_ASSERT_UNREACHABLE("Calling IsFinished() on a placeholder");
    return false;
  }

  if (!mSurface) {
    MOZ_ASSERT_UNREACHABLE("Calling IsFinished() when we have no surface");
    return false;
  }

  return mSurface->IsFinished();
}

void
DecodedSurfaceProvider::SetLocked(bool aLocked)
{
  // See DrawableRef() for commentary on these assertions.
  if (Availability().IsPlaceholder()) {
    MOZ_ASSERT_UNREACHABLE("Calling SetLocked() on a placeholder");
    return;
  }

  if (!mSurface) {
    MOZ_ASSERT_UNREACHABLE("Calling SetLocked() when we have no surface");
    return;
  }

  if (aLocked == IsLocked()) {
    return;  // Nothing to do.
  }

  // If we're locked, hold a DrawableFrameRef to |mSurface|, which will keep any
  // volatile buffer it owns in memory.
  mLockRef = aLocked ? mSurface->DrawableRef()
                     : DrawableFrameRef();
}

size_t
DecodedSurfaceProvider::LogicalSizeInBytes() const
{
  // Single frame images are always 32bpp.
  IntSize size = GetSurfaceKey().Size();
  return size.width * size.height * sizeof(uint32_t);
}

void
DecodedSurfaceProvider::Run()
{
  MutexAutoLock lock(mMutex);

  if (!mDecoder || !mImage) {
    MOZ_ASSERT_UNREACHABLE("Running after decoding finished?");
    return;
  }

  // Run the decoder.
  LexerResult result = mDecoder->Decode(WrapNotNull(this));

  // If there's a new surface available, announce it to the surface cache.
  CheckForNewSurface();

  if (result.is<TerminalState>()) {
    FinishDecoding();
    return;  // We're done.
  }

  // Notify for the progress we've made so far.
  if (mDecoder->HasProgress()) {
    NotifyProgress(WrapNotNull(mImage), WrapNotNull(mDecoder));
  }

  MOZ_ASSERT(result.is<Yield>());

  if (result == LexerResult(Yield::NEED_MORE_DATA)) {
    // We can't make any more progress right now. The decoder itself will ensure
    // that we get reenqueued when more data is available; just return for now.
    return;
  }

  // Single-frame images shouldn't yield for any reason except NEED_MORE_DATA.
  MOZ_ASSERT_UNREACHABLE("Unexpected yield for single-frame image");
  mDecoder->TerminateFailure();
  FinishDecoding();
}

void
DecodedSurfaceProvider::CheckForNewSurface()
{
  mMutex.AssertCurrentThreadOwns();
  MOZ_ASSERT(mDecoder);

  if (mSurface) {
    // Single-frame images should produce no more than one surface, so if we
    // have one, it should be the same one the decoder is working on.
    MOZ_ASSERT(mSurface.get() == mDecoder->GetCurrentFrameRef().get(),
               "DecodedSurfaceProvider and Decoder have different surfaces?");
    return;
  }

  // We don't have a surface yet; try to get one from the decoder.
  mSurface = mDecoder->GetCurrentFrameRef().get();
  if (!mSurface) {
    return;  // No surface yet.
  }

  // We just got a surface for the first time; let the surface cache know.
  MOZ_ASSERT(mImage);
  SurfaceCache::SurfaceAvailable(WrapNotNull(this));
}

void
DecodedSurfaceProvider::FinishDecoding()
{
  mMutex.AssertCurrentThreadOwns();
  MOZ_ASSERT(mImage);
  MOZ_ASSERT(mDecoder);

  // Send notifications.
  NotifyDecodeComplete(WrapNotNull(mImage), WrapNotNull(mDecoder));

  // Destroy our decoder; we don't need it anymore. (And if we don't destroy it,
  // our surface can never be optimized, because the decoder has a
  // RawAccessFrameRef to it.)
  mDecoder = nullptr;

  // We don't need a reference to our image anymore, either, and we don't want
  // one. We may be stored in the surface cache for a long time after decoding
  // finishes. If we don't drop our reference to the image, we'll end up
  // keeping it alive as long as we remain in the surface cache, which could
  // greatly extend the image's lifetime - in fact, if the image isn't
  // discardable, it'd result in a leak!
  DropImageReference();
}

bool
DecodedSurfaceProvider::ShouldPreferSyncRun() const
{
  return mDecoder->ShouldSyncDecode(gfxPrefs::ImageMemDecodeBytesAtATime());
}

} // namespace image
} // namespace mozilla