allocator.h

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// 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.
 
#ifndef FLUTTER_IMPELLER_CORE_ALLOCATOR_H_
#define FLUTTER_IMPELLER_CORE_ALLOCATOR_H_
 
#include "flutter/fml/mapping.h"
#include "impeller/base/allocation_size.h"
#include "impeller/core/device_buffer_descriptor.h"
#include "impeller/core/idle_waiter.h"
#include "impeller/core/texture.h"
#include "impeller/core/texture_descriptor.h"
#include "impeller/geometry/size.h"
 
namespace impeller {
 
class Context;
class DeviceBuffer;
 
//------------------------------------------------------------------------------
/// @brief      An object that allocates device memory.
///
class Allocator {
 public:
  virtual ~Allocator();
 
  bool IsValid() const;
 
  std::shared_ptr<DeviceBuffer> CreateBuffer(
      const DeviceBufferDescriptor& desc);
 
  //------------------------------------------------------------------------------
  /// @brief      Creates a new texture.
  ///
  /// @param[in]  desc        The descriptor of the texture to create.
  /// @param[in]  threadsafe  Whether mutations to this texture should be
  ///                         protected with a threadsafe barrier.
  ///
  ///                         This parameter only affects the OpenGLES rendering
  ///                         backend.
  ///
  ///                         If any interaction with this texture (including
  ///                         creation) will be done on a thread other than
  ///                         where the OpenGLES context resides, then
  ///                         `threadsafe`, must be set to `true`.
  ///
  std::shared_ptr<Texture> CreateTexture(const TextureDescriptor& desc,
                                         bool threadsafe = false);
 
  //------------------------------------------------------------------------------
  /// @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 Write debug memory usage information to the dart timeline in debug
  ///        and profile modes.
  ///
  ///        This is supported on both the Metal and Vulkan backends.
  virtual void DebugTraceMemoryStatistics() const {};
 
  // Visible for testing.
  virtual Bytes DebugGetHeapUsage() const { return Bytes{0}; }
 
 protected:
  Allocator();
 
  virtual std::shared_ptr<DeviceBuffer> OnCreateBuffer(
      const DeviceBufferDescriptor& desc) = 0;
 
  virtual std::shared_ptr<Texture> OnCreateTexture(
      const TextureDescriptor& desc,
      bool threadsafe = false) = 0;
 
 private:
  Allocator(const Allocator&) = delete;
 
  Allocator& operator=(const Allocator&) = delete;
};
 
}  // namespace impeller
 
#endif  // FLUTTER_IMPELLER_CORE_ALLOCATOR_H_