impeller/core/allocator.h

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include "flutter/fml/mapping.h"
#include "impeller/core/device_buffer_descriptor.h"
#include "impeller/core/texture.h"
#include "impeller/core/texture_descriptor.h"
#include "impeller/geometry/size.h"

namespace impeller {

class Context;
class DeviceBuffer;
class Texture;

//------------------------------------------------------------------------------
/// @brief      An object that allocates device memory.
///
class Allocator {
 public:
  virtual ~Allocator();

  bool IsValid() const;

  std::shared_ptr<DeviceBuffer> CreateBuffer(
      const DeviceBufferDescriptor& desc);

  std::shared_ptr<Texture> CreateTexture(const TextureDescriptor& desc);

  //------------------------------------------------------------------------------
  /// @brief      Minimum value for `row_bytes` on a Texture. The row
  ///             bytes parameter of that method must be aligned to this value.
  ///
  virtual uint16_t MinimumBytesPerRow(PixelFormat format) const;

  std::shared_ptr<DeviceBuffer> CreateBufferWithCopy(const uint8_t* buffer,
                                                     size_t length);

  std::shared_ptr<DeviceBuffer> CreateBufferWithCopy(
      const fml::Mapping& mapping);

  virtual ISize GetMaxTextureSizeSupported() const = 0;

  /// @brief Increment an internal frame used to cycle through a ring buffer of
  /// allocation pools.
  virtual void DidAcquireSurfaceFrame();

 protected:
  Allocator();

  virtual std::shared_ptr<DeviceBuffer> OnCreateBuffer(
      const DeviceBufferDescriptor& desc) = 0;

  virtual std::shared_ptr<Texture> OnCreateTexture(
      const TextureDescriptor& desc) = 0;

 private:
  Allocator(const Allocator&) = delete;

  Allocator& operator=(const Allocator&) = delete;
};

}  // namespace impeller