image/DecodedSurfaceProvider.cpp
author Henrik Skupin <mail@hskupin.info>
Fri, 30 Nov 2018 13:27:22 +0000
changeset 448968 cd370c35d88d82c719e7b3d70ae1da003c8cb7f6
parent 448947 6f3709b3878117466168c40affa7bca0b60cf75b
child 475076 898ed02804fefc9786112f135b9621cc444e6860
permissions -rw-r--r--
Bug 1511311 - [marionette] GeckoInstance classes should not overwrite already set custom preferences. r=automatedtester Custom preferences as passed into both classes via the constructor are getting set in the base GeckoInstance class. But both the DesktopInstance and FennecInstance classes could override those custom preferences if they have the same preference set as required preference. As such the custom preference doesn't have any effect. This patch allows both classes to override required prefs with a different value. Differential Revision: https://phabricator.services.mozilla.com/D13522

/* -*- 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_t(size.width) * size_t(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));

  // If we have a new and complete surface, we can try to prune similarly sized
  // surfaces if the cache supports it.
  if (mSurface && mSurface->IsFinished()) {
    SurfaceCache::PruneImage(ImageKey(mImage));
  }

  // 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