// Copyright (c) 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/paint/image_transfer_cache_entry.h"

#include "base/bind_helpers.h"
#include "base/logging.h"
#include "base/numerics/checked_math.h"
#include "cc/paint/paint_op_reader.h"
#include "cc/paint/paint_op_writer.h"
#include "third_party/skia/include/gpu/GrContext.h"

namespace cc {
namespace {

// TODO(ericrk): Replace calls to this with calls to SkImage::makeTextureImage,
// once that function handles colorspaces. https://crbug.com/834837
sk_sp<SkImage> MakeTextureImage(GrContext* context,
                                sk_sp<SkImage> source_image,
                                sk_sp<SkColorSpace> target_color_space,
                                GrMipMapped mip_mapped) {
  // Step 1: Upload image and generate mips if necessary. If we will be applying
  // a color-space conversion, don't generate mips yet, instead do it after
  // conversion, in step 3.
  // NOTE: |target_color_space| is only passed over the transfer cache if needed
  // (non-null, different from the source color space).
  bool add_mips_after_color_conversion =
      target_color_space && mip_mapped == GrMipMapped::kYes;
  sk_sp<SkImage> uploaded_image = source_image->makeTextureImage(
      context, nullptr,
      add_mips_after_color_conversion ? GrMipMapped::kNo : mip_mapped);

  // Step 2: Apply a color-space conversion if necessary.
  if (uploaded_image && target_color_space) {
    // TODO(ericrk): consider adding in the DeleteSkImageAndPreventCaching
    // optimization from GpuImageDecodeCache where we forcefully remove the
    // intermediate from Skia's cache.
    uploaded_image = uploaded_image->makeColorSpace(target_color_space);
  }

  // Step 3: If we had a colorspace conversion, we couldn't mipmap in step 1, so
  // add mips here.
  if (uploaded_image && add_mips_after_color_conversion) {
    // TODO(ericrk): consider adding in the DeleteSkImageAndPreventCaching
    // optimization from GpuImageDecodeCache where we forcefully remove the
    // intermediate from Skia's cache.
    uploaded_image =
        uploaded_image->makeTextureImage(context, nullptr, GrMipMapped::kYes);
  }

  return uploaded_image;
}

}  // namespace

ClientImageTransferCacheEntry::ClientImageTransferCacheEntry(
    const SkPixmap* pixmap,
    const SkColorSpace* target_color_space,
    bool needs_mips)
    : id_(s_next_id_.GetNext()),
      pixmap_(pixmap),
      target_color_space_(target_color_space),
      needs_mips_(needs_mips) {
  size_t target_color_space_size =
      target_color_space ? target_color_space->writeToMemory(nullptr) : 0u;
  size_t pixmap_color_space_size =
      pixmap_->colorSpace() ? pixmap_->colorSpace()->writeToMemory(nullptr)
                            : 0u;

  // Compute and cache the size of the data.
  base::CheckedNumeric<uint32_t> safe_size;
  safe_size += PaintOpWriter::HeaderBytes();
  safe_size += sizeof(uint32_t);  // color type
  safe_size += sizeof(uint32_t);  // width
  safe_size += sizeof(uint32_t);  // height
  safe_size += sizeof(uint32_t);  // has mips
  safe_size += sizeof(uint64_t) + alignof(uint64_t);  // pixels size
  safe_size += target_color_space_size + sizeof(uint64_t) + alignof(uint64_t);
  safe_size += pixmap_color_space_size + sizeof(uint64_t) + alignof(uint64_t);
  // Include 4 bytes of padding so we can always align our data pointer to a
  // 4-byte boundary.
  safe_size += 4;
  safe_size += pixmap_->computeByteSize();
  size_ = safe_size.ValueOrDie();
}

ClientImageTransferCacheEntry::~ClientImageTransferCacheEntry() = default;

// static
base::AtomicSequenceNumber ClientImageTransferCacheEntry::s_next_id_;

uint32_t ClientImageTransferCacheEntry::SerializedSize() const {
  return size_;
}

uint32_t ClientImageTransferCacheEntry::Id() const {
  return id_;
}

bool ClientImageTransferCacheEntry::Serialize(base::span<uint8_t> data) const {
  DCHECK_GE(data.size(), SerializedSize());

  // We don't need to populate the SerializeOptions here since the writer is
  // only used for serializing primitives.
  PaintOp::SerializeOptions options(nullptr, nullptr, nullptr, nullptr, nullptr,
                                    nullptr, false, false, 0, 0, SkMatrix::I());
  PaintOpWriter writer(data.data(), data.size(), options);
  writer.Write(pixmap_->colorType());
  writer.Write(pixmap_->width());
  writer.Write(pixmap_->height());
  writer.Write(static_cast<uint32_t>(needs_mips_ ? 1 : 0));
  size_t pixmap_size = pixmap_->computeByteSize();
  writer.WriteSize(pixmap_size);
  // TODO(enne): we should consider caching these in some form.
  writer.Write(pixmap_->colorSpace());
  writer.Write(target_color_space_);
  writer.AlignMemory(4);
  writer.WriteData(pixmap_size, pixmap_->addr());

  // Size can't be 0 after serialization unless the writer has become invalid.
  if (writer.size() == 0u)
    return false;

  return true;
}

ServiceImageTransferCacheEntry::ServiceImageTransferCacheEntry() = default;
ServiceImageTransferCacheEntry::~ServiceImageTransferCacheEntry() = default;

ServiceImageTransferCacheEntry::ServiceImageTransferCacheEntry(
    ServiceImageTransferCacheEntry&& other) = default;
ServiceImageTransferCacheEntry& ServiceImageTransferCacheEntry::operator=(
    ServiceImageTransferCacheEntry&& other) = default;

size_t ServiceImageTransferCacheEntry::CachedSize() const {
  return size_;
}

bool ServiceImageTransferCacheEntry::Deserialize(
    GrContext* context,
    base::span<const uint8_t> data) {
  context_ = context;

  // We don't need to populate the DeSerializeOptions here since the reader is
  // only used for de-serializing primitives.
  std::vector<uint8_t> scratch_buffer;
  PaintOp::DeserializeOptions options(nullptr, nullptr, nullptr,
                                      &scratch_buffer);
  PaintOpReader reader(data.data(), data.size(), options);
  SkColorType color_type;
  reader.Read(&color_type);
  uint32_t width;
  reader.Read(&width);
  uint32_t height;
  reader.Read(&height);
  uint32_t needs_mips;
  reader.Read(&needs_mips);
  has_mips_ = needs_mips;
  size_t pixel_size;
  reader.ReadSize(&pixel_size);
  size_ = data.size();
  sk_sp<SkColorSpace> pixmap_color_space;
  reader.Read(&pixmap_color_space);
  sk_sp<SkColorSpace> target_color_space;
  reader.Read(&target_color_space);

  if (!reader.valid())
    return false;

  SkImageInfo image_info = SkImageInfo::Make(
      width, height, color_type, kPremul_SkAlphaType, pixmap_color_space);
  if (image_info.computeMinByteSize() > pixel_size)
    return false;

  // Align data to a 4-byte boundry, to match what we did when writing.
  reader.AlignMemory(4);
  const volatile void* pixel_data = reader.ExtractReadableMemory(pixel_size);
  if (!reader.valid())
    return false;

  DCHECK(SkIsAlign4(reinterpret_cast<uintptr_t>(pixel_data)));

  // Const-cast away the "volatile" on |pixel_data|. We specifically understand
  // that a malicious caller may change our pixels under us, and are OK with
  // this as the worst case scenario is visual corruption.
  SkPixmap pixmap(image_info, const_cast<const void*>(pixel_data),
                  image_info.minRowBytes());

  // Depending on whether the pixmap will fit in a GPU texture, either create
  // a software or GPU SkImage.
  uint32_t max_size = context->maxTextureSize();
  fits_on_gpu_ = width <= max_size && height <= max_size;
  if (fits_on_gpu_) {
    sk_sp<SkImage> image = SkImage::MakeFromRaster(pixmap, nullptr, nullptr);
    if (!image)
      return false;
    image_ =
        MakeTextureImage(context, std::move(image), target_color_space,
                         needs_mips ? GrMipMapped::kYes : GrMipMapped::kNo);
  } else {
    sk_sp<SkImage> original =
        SkImage::MakeFromRaster(pixmap, [](const void*, void*) {}, nullptr);
    if (!original)
      return false;
    if (target_color_space) {
      image_ = original->makeColorSpace(target_color_space);
      // If color space conversion is a noop, use original data.
      if (image_ == original)
        image_ = SkImage::MakeRasterCopy(pixmap);
    } else {
      // No color conversion to do, use original data.
      image_ = SkImage::MakeRasterCopy(pixmap);
    }
  }

  return !!image_;
}

void ServiceImageTransferCacheEntry::EnsureMips() {
  if (has_mips_)
    return;

  has_mips_ = true;
  // TODO(ericrk): consider adding in the DeleteSkImageAndPreventCaching
  // optimization from GpuImageDecodeCache where we forcefully remove the
  // intermediate from Skia's cache.
  image_ = image_->makeTextureImage(context_, nullptr, GrMipMapped::kYes);
}

}  // namespace cc