// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_MEMORY_MANAGED_PAINT_CANVAS_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_MEMORY_MANAGED_PAINT_CANVAS_H_

#include "cc/paint/paint_canvas.h"
#include "cc/paint/record_paint_canvas.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/wtf/casting.h"
#include "third_party/blink/renderer/platform/wtf/hash_set.h"

namespace blink {

// MemoryManagedPaintCanvas overrides the potentially memory intensive image
// drawing methods of PaintCanvas and keeps track of how much memory is
// being pinned between flushes. This allows the rendering context to flush if
// too much memory is used.

class PLATFORM_EXPORT MemoryManagedPaintCanvas final
    : public cc::InspectableRecordPaintCanvas {
 public:
  explicit MemoryManagedPaintCanvas(const gfx::Size& size);
  explicit MemoryManagedPaintCanvas(const cc::RecordPaintCanvas&) = delete;
  ~MemoryManagedPaintCanvas() override;

  std::unique_ptr<MemoryManagedPaintCanvas> CreateChildCanvas();

  cc::PaintRecord ReleaseAsRecord() override;

  void drawImage(const cc::PaintImage& image,
                 SkScalar left,
                 SkScalar top,
                 const SkSamplingOptions&,
                 const cc::PaintFlags* flags) override;
  void drawImageRect(const cc::PaintImage& image,
                     const SkRect& src,
                     const SkRect& dst,
                     const SkSamplingOptions&,
                     const cc::PaintFlags* flags,
                     SkCanvas::SrcRectConstraint constraint) override;

  bool IsCachingImage(const cc::PaintImage::ContentId content_id) const;
  size_t ImageBytesUsed() const { return image_bytes_used_; }

 private:
  // Creates a child canvas that has the same transform matrix and size as
  // `parent`. `CreateChildCanvasTag` is used to differentiate this from a copy
  // constructor.
  MemoryManagedPaintCanvas(CreateChildCanvasTag,
                           const MemoryManagedPaintCanvas& parent);

  void UpdateMemoryUsage(const cc::PaintImage& image);

  HashSet<cc::PaintImage::ContentId,
          IntWithZeroKeyHashTraits<cc::PaintImage::ContentId>>
      cached_image_ids_;

  // Total size of images stored in this recording.
  size_t image_bytes_used_ = 0;
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_MEMORY_MANAGED_PAINT_CANVAS_H_