gecko-dev/image/IDecodingTask.cpp

/* -*- 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 "IDecodingTask.h"

#include "gfxPrefs.h"
#include "nsThreadUtils.h"

#include "Decoder.h"
#include "DecodePool.h"
#include "RasterImage.h"

namespace mozilla {
namespace image {

///////////////////////////////////////////////////////////////////////////////
// Helpers for sending notifications to the image associated with a decoder.
///////////////////////////////////////////////////////////////////////////////

/* static */ void
IDecodingTask::NotifyProgress(NotNull<Decoder*> aDecoder)
{
  MOZ_ASSERT(aDecoder->HasProgress() && !aDecoder->IsMetadataDecode());

  // Synchronously notify if we can.
  if (NS_IsMainThread() &&
      !(aDecoder->GetDecoderFlags() & DecoderFlags::ASYNC_NOTIFY)) {
    aDecoder->GetImage()->NotifyProgress(aDecoder->TakeProgress(),
                                         aDecoder->TakeInvalidRect(),
                                         aDecoder->GetSurfaceFlags());
    return;
  }

  // We're forced to notify asynchronously.
  NotNull<RefPtr<Decoder>> decoder = aDecoder;
  NS_DispatchToMainThread(NS_NewRunnableFunction([=]() -> void {
    decoder->GetImage()->NotifyProgress(decoder->TakeProgress(),
                                        decoder->TakeInvalidRect(),
                                        decoder->GetSurfaceFlags());
  }));
}

static void
NotifyDecodeComplete(NotNull<Decoder*> aDecoder)
{
  // Synchronously notify if we can.
  if (NS_IsMainThread() &&
      !(aDecoder->GetDecoderFlags() & DecoderFlags::ASYNC_NOTIFY)) {
    aDecoder->GetImage()->FinalizeDecoder(aDecoder);
    return;
  }

  // We're forced to notify asynchronously.
  NotNull<RefPtr<Decoder>> decoder = aDecoder;
  NS_DispatchToMainThread(NS_NewRunnableFunction([=]() -> void {
    decoder->GetImage()->FinalizeDecoder(decoder.get());
  }));
}


///////////////////////////////////////////////////////////////////////////////
// IDecodingTask implementation.
///////////////////////////////////////////////////////////////////////////////

void
IDecodingTask::Resume()
{
  DecodePool::Singleton()->AsyncRun(this);
}


///////////////////////////////////////////////////////////////////////////////
// DecodingTask implementation.
///////////////////////////////////////////////////////////////////////////////

DecodingTask::DecodingTask(NotNull<Decoder*> aDecoder)
  : mDecoder(aDecoder)
{
  MOZ_ASSERT(!mDecoder->IsMetadataDecode(),
             "Use MetadataDecodingTask for metadata decodes");
}

void
DecodingTask::Run()
{
  nsresult rv = mDecoder->Decode(WrapNotNull(this));

  if (NS_SUCCEEDED(rv) && !mDecoder->GetDecodeDone()) {
    // Notify for the progress we've made so far.
    if (mDecoder->HasProgress()) {
      NotifyProgress(mDecoder);
    }

    // We don't need to do anything else for this case. The decoder itself will
    // ensure that we get reenqueued when more data is available.
    return;
  }

  NotifyDecodeComplete(mDecoder);
}

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


///////////////////////////////////////////////////////////////////////////////
// MetadataDecodingTask implementation.
///////////////////////////////////////////////////////////////////////////////

MetadataDecodingTask::MetadataDecodingTask(NotNull<Decoder*> aDecoder)
  : mDecoder(aDecoder)
{
  MOZ_ASSERT(mDecoder->IsMetadataDecode(),
             "Use DecodingTask for non-metadata decodes");
}

void
MetadataDecodingTask::Run()
{
  nsresult rv = mDecoder->Decode(WrapNotNull(this));

  if (NS_SUCCEEDED(rv) && !mDecoder->GetDecodeDone()) {
    // It's important that metadata decode results are delivered atomically, so
    // we'll wait until NotifyDecodeComplete() to report any progress.  We don't
    // need to do anything else for this case. The decoder itself will ensure
    // that we get reenqueued when more data is available.
    return;
  }

  NotifyDecodeComplete(mDecoder);
}


///////////////////////////////////////////////////////////////////////////////
// AnonymousDecodingTask implementation.
///////////////////////////////////////////////////////////////////////////////

AnonymousDecodingTask::AnonymousDecodingTask(NotNull<Decoder*> aDecoder)
  : mDecoder(aDecoder)
{ }

void
AnonymousDecodingTask::Run()
{
  mDecoder->Decode(WrapNotNull(this));
}

} // namespace image
} // namespace mozilla