DataSurfaceHelpers.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 <cstring>

#include "2D.h"
#include "DataSurfaceHelpers.h"
#include "Logging.h"
#include "mozilla/MathAlgorithms.h"
#include "mozilla/PodOperations.h"
#include "Swizzle.h"
#include "Tools.h"

namespace mozilla {
namespace gfx {

int32_t StrideForFormatAndWidth(SurfaceFormat aFormat, int32_t aWidth) {
  MOZ_ASSERT(aFormat <= SurfaceFormat::UNKNOWN);
  MOZ_ASSERT(aWidth > 0);

  // There's nothing special about this alignment, other than that it's what
  // cairo_format_stride_for_width uses.
  static const int32_t alignment = sizeof(int32_t);

  const int32_t bpp = BytesPerPixel(aFormat);

  if (aWidth >= (INT32_MAX - alignment) / bpp) {
    return -1;  // too big
  }

  return (bpp * aWidth + alignment - 1) & ~(alignment - 1);
}

already_AddRefed<DataSourceSurface> CreateDataSourceSurfaceFromData(
    const IntSize& aSize, SurfaceFormat aFormat, const uint8_t* aData,
    int32_t aDataStride) {
  RefPtr<DataSourceSurface> srcSurface =
      Factory::CreateWrappingDataSourceSurface(const_cast<uint8_t*>(aData),
                                               aDataStride, aSize, aFormat);
  RefPtr<DataSourceSurface> destSurface =
      Factory::CreateDataSourceSurface(aSize, aFormat, false);

  if (!srcSurface || !destSurface) {
    return nullptr;
  }

  if (CopyRect(srcSurface, destSurface,
               IntRect(IntPoint(), srcSurface->GetSize()), IntPoint())) {
    return destSurface.forget();
  }

  return nullptr;
}

already_AddRefed<DataSourceSurface> CreateDataSourceSurfaceWithStrideFromData(
    const IntSize& aSize, SurfaceFormat aFormat, int32_t aStride,
    const uint8_t* aData, int32_t aDataStride) {
  RefPtr<DataSourceSurface> srcSurface =
      Factory::CreateWrappingDataSourceSurface(const_cast<uint8_t*>(aData),
                                               aDataStride, aSize, aFormat);
  RefPtr<DataSourceSurface> destSurface =
      Factory::CreateDataSourceSurfaceWithStride(aSize, aFormat, aStride,
                                                 false);

  if (!srcSurface || !destSurface) {
    return nullptr;
  }

  if (CopyRect(srcSurface, destSurface,
               IntRect(IntPoint(), srcSurface->GetSize()), IntPoint())) {
    return destSurface.forget();
  }

  return nullptr;
}

uint8_t* DataAtOffset(DataSourceSurface* aSurface,
                      const DataSourceSurface::MappedSurface* aMap,
                      IntPoint aPoint) {
  if (!SurfaceContainsPoint(aSurface, aPoint)) {
    MOZ_CRASH("GFX: sample position needs to be inside surface!");
  }

  MOZ_ASSERT(Factory::CheckSurfaceSize(aSurface->GetSize()),
             "surface size overflows - this should have been prevented when "
             "the surface was created");

  uint8_t* data = aMap->mData + aPoint.y * aMap->mStride +
                  aPoint.x * BytesPerPixel(aSurface->GetFormat());

  if (data < aMap->mData) {
    MOZ_CRASH("GFX: out-of-range data access");
  }

  return data;
}

// This check is safe against integer overflow.
bool SurfaceContainsPoint(SourceSurface* aSurface, const IntPoint& aPoint) {
  IntSize size = aSurface->GetSize();
  return aPoint.x >= 0 && aPoint.x < size.width && aPoint.y >= 0 &&
         aPoint.y < size.height;
}

void CopySurfaceDataToPackedArray(uint8_t* aSrc, uint8_t* aDst,
                                  IntSize aSrcSize, int32_t aSrcStride,
                                  int32_t aBytesPerPixel) {
  MOZ_ASSERT(aBytesPerPixel > 0,
             "Negative stride for aDst not currently supported");
  MOZ_ASSERT(BufferSizeFromStrideAndHeight(aSrcStride, aSrcSize.height) > 0,
             "How did we end up with a surface with such a big buffer?");

  int packedStride = aSrcSize.width * aBytesPerPixel;

  if (aSrcStride == packedStride) {
    // aSrc is already packed, so we can copy with a single memcpy.
    memcpy(aDst, aSrc, packedStride * aSrcSize.height);
  } else {
    // memcpy one row at a time.
    for (int row = 0; row < aSrcSize.height; ++row) {
      memcpy(aDst, aSrc, packedStride);
      aSrc += aSrcStride;
      aDst += packedStride;
    }
  }
}

UniquePtr<uint8_t[]> SurfaceToPackedBGRA(DataSourceSurface* aSurface) {
  SurfaceFormat format = aSurface->GetFormat();
  if (format != SurfaceFormat::B8G8R8A8 && format != SurfaceFormat::B8G8R8X8) {
    return nullptr;
  }

  IntSize size = aSurface->GetSize();
  if (size.width < 0 || size.width >= INT32_MAX / 4) {
    return nullptr;
  }
  int32_t stride = size.width * 4;
  CheckedInt<size_t> bufferSize =
      CheckedInt<size_t>(stride) * CheckedInt<size_t>(size.height);
  if (!bufferSize.isValid()) {
    return nullptr;
  }
  UniquePtr<uint8_t[]> imageBuffer(new (std::nothrow)
                                       uint8_t[bufferSize.value()]);
  if (!imageBuffer) {
    return nullptr;
  }

  DataSourceSurface::MappedSurface map;
  if (!aSurface->Map(DataSourceSurface::MapType::READ, &map)) {
    return nullptr;
  }

  CopySurfaceDataToPackedArray(map.mData, imageBuffer.get(), size, map.mStride,
                               4);

  aSurface->Unmap();

  if (format == SurfaceFormat::B8G8R8X8) {
    // Convert BGRX to BGRA by setting a to 255.
    SwizzleData(imageBuffer.get(), stride, SurfaceFormat::X8R8G8B8_UINT32,
                imageBuffer.get(), stride, SurfaceFormat::A8R8G8B8_UINT32,
                size);
  }

  return imageBuffer;
}

uint8_t* SurfaceToPackedBGR(DataSourceSurface* aSurface) {
  SurfaceFormat format = aSurface->GetFormat();
  MOZ_ASSERT(format == SurfaceFormat::B8G8R8X8, "Format not supported");

  if (format != SurfaceFormat::B8G8R8X8) {
    // To support B8G8R8A8 we'd need to un-pre-multiply alpha
    return nullptr;
  }

  IntSize size = aSurface->GetSize();
  if (size.width < 0 || size.width >= INT32_MAX / 3) {
    return nullptr;
  }
  int32_t stride = size.width * 3;
  CheckedInt<size_t> bufferSize =
      CheckedInt<size_t>(stride) * CheckedInt<size_t>(size.height);
  if (!bufferSize.isValid()) {
    return nullptr;
  }
  uint8_t* imageBuffer = new (std::nothrow) uint8_t[bufferSize.value()];
  if (!imageBuffer) {
    return nullptr;
  }

  DataSourceSurface::MappedSurface map;
  if (!aSurface->Map(DataSourceSurface::MapType::READ, &map)) {
    delete[] imageBuffer;
    return nullptr;
  }

  SwizzleData(map.mData, map.mStride, SurfaceFormat::B8G8R8X8, imageBuffer,
              stride, SurfaceFormat::B8G8R8, size);

  aSurface->Unmap();

  return imageBuffer;
}

void ClearDataSourceSurface(DataSourceSurface* aSurface) {
  DataSourceSurface::MappedSurface map;
  if (!aSurface->Map(DataSourceSurface::MapType::WRITE, &map)) {
    MOZ_ASSERT(false, "Failed to map DataSourceSurface");
    return;
  }

  // We avoid writing into the gaps between the rows here since we can't be
  // sure that some drivers don't use those bytes.

  uint32_t width = aSurface->GetSize().width;
  uint32_t bytesPerRow = width * BytesPerPixel(aSurface->GetFormat());
  uint8_t* row = map.mData;
  // converting to size_t here because otherwise the temporaries can overflow
  // and we can end up with |end| being a bad address!
  uint8_t* end = row + size_t(map.mStride) * size_t(aSurface->GetSize().height);

  while (row != end) {
    memset(row, 0, bytesPerRow);
    row += map.mStride;
  }

  aSurface->Unmap();
}

size_t BufferSizeFromStrideAndHeight(int32_t aStride, int32_t aHeight,
                                     int32_t aExtraBytes) {
  if (MOZ_UNLIKELY(aHeight <= 0) || MOZ_UNLIKELY(aStride <= 0)) {
    return 0;
  }

  // We limit the length returned to values that can be represented by int32_t
  // because we don't want to allocate buffers any bigger than that. This
  // allows for a buffer size of over 2 GiB which is already rediculously
  // large and will make the process janky. (Note the choice of the signed type
  // is deliberate because we specifically don't want the returned value to
  // overflow if someone stores the buffer length in an int32_t variable.)

  CheckedInt32 requiredBytes =
      CheckedInt32(aStride) * CheckedInt32(aHeight) + CheckedInt32(aExtraBytes);
  if (MOZ_UNLIKELY(!requiredBytes.isValid())) {
    gfxWarning() << "Buffer size too big; returning zero " << aStride << ", "
                 << aHeight << ", " << aExtraBytes;
    return 0;
  }
  return requiredBytes.value();
}

size_t BufferSizeFromDimensions(int32_t aWidth, int32_t aHeight, int32_t aDepth,
                                int32_t aExtraBytes) {
  if (MOZ_UNLIKELY(aHeight <= 0) || MOZ_UNLIKELY(aWidth <= 0) ||
      MOZ_UNLIKELY(aDepth <= 0)) {
    return 0;
  }

  // Similar to BufferSizeFromStrideAndHeight, but with an extra parameter.

  CheckedInt32 requiredBytes =
      CheckedInt32(aWidth) * CheckedInt32(aHeight) * CheckedInt32(aDepth) +
      CheckedInt32(aExtraBytes);
  if (MOZ_UNLIKELY(!requiredBytes.isValid())) {
    gfxWarning() << "Buffer size too big; returning zero " << aWidth << ", "
                 << aHeight << ", " << aDepth << ", " << aExtraBytes;
    return 0;
  }
  return requiredBytes.value();
}

/**
 * aSrcRect: Rect relative to the aSrc surface
 * aDestPoint: Point inside aDest surface
 *
 * aSrcRect and aDestPoint are in internal local coordinates.
 * i.e. locations of pixels and not in the same coordinate space
 * as aSrc->GetRect()
 */
bool CopyRect(DataSourceSurface* aSrc, DataSourceSurface* aDest,
              IntRect aSrcRect, IntPoint aDestPoint) {
  if (aSrcRect.Overflows() ||
      IntRect(aDestPoint, aSrcRect.Size()).Overflows()) {
    MOZ_CRASH("GFX: we should never be getting invalid rects at this point");
  }

  MOZ_RELEASE_ASSERT(aSrc->GetFormat() == aDest->GetFormat(),
                     "GFX: different surface formats");
  MOZ_RELEASE_ASSERT(IntRect(IntPoint(), aSrc->GetSize()).Contains(aSrcRect),
                     "GFX: source rect too big for source surface");
  MOZ_RELEASE_ASSERT(IntRect(IntPoint(), aDest->GetSize())
                         .Contains(IntRect(aDestPoint, aSrcRect.Size())),
                     "GFX: dest surface too small");

  if (aSrcRect.IsEmpty()) {
    return false;
  }

  DataSourceSurface::ScopedMap srcMap(aSrc, DataSourceSurface::READ);
  DataSourceSurface::ScopedMap destMap(aDest, DataSourceSurface::WRITE);
  if (MOZ2D_WARN_IF(!srcMap.IsMapped() || !destMap.IsMapped())) {
    return false;
  }

  uint8_t* sourceData =
      DataAtOffset(aSrc, srcMap.GetMappedSurface(), aSrcRect.TopLeft());
  uint8_t* destData =
      DataAtOffset(aDest, destMap.GetMappedSurface(), aDestPoint);

  SwizzleData(sourceData, srcMap.GetStride(), aSrc->GetFormat(), destData,
              destMap.GetStride(), aDest->GetFormat(), aSrcRect.Size());

  return true;
}

already_AddRefed<DataSourceSurface> CreateDataSourceSurfaceByCloning(
    DataSourceSurface* aSource) {
  RefPtr<DataSourceSurface> copy = Factory::CreateDataSourceSurface(
      aSource->GetSize(), aSource->GetFormat(), true);
  if (copy) {
    CopyRect(aSource, copy, IntRect(IntPoint(), aSource->GetSize()),
             IntPoint());
  }
  return copy.forget();
}

}  // namespace gfx
}  // namespace mozilla