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/*
* Copyright (C) 2017-2018 Team Kodi
* This file is part of Kodi - https://kodi.tv
*
* SPDX-License-Identifier: GPL-2.0-or-later
* See LICENSES/README.md for more information.
*/
#pragma once
#include <stdint.h>
#include <string>
/**
* @brief Interface to describe CBufferObjects.
*
* BufferObjects are used to abstract various memory types and present them
* with a generic interface. Typically on a posix system exists the concept
* of Direct Memory Access (DMA) which allows various systems to interact
* with a memory location directly without having to copy the data into
* userspace (ie. from kernel space). These DMA buffers are presented as
* file descriptors (fds) which can be passed around to gain access to
* the buffers memory location.
*
* In order to write to these buffer types typically the memory location has
* to be mapped into userspace via a call to mmap (or similar). This presents
* userspace with a memory location that can be initially written to (ie. by
* using memcpy or similar). Depending on the underlying implementation a
* stride might be specified if the memory type requires padding to a certain
* size (such as page size). The stride must be used when copying into the buffer.
*
* Some memory implementation may provide special memory layouts in which case
* modifiers are provided that describe tiling or compression. This should be
* transparent to the caller as the data copied into a BufferObject will likely
* be linear. The modifier will be needed when presenting the buffer via DRM or
* EGL even if it is linear.
*
*/
class IBufferObject
{
public:
virtual ~IBufferObject() = default;
/**
* @brief Create a BufferObject based on the format, width, and height of the desired buffer
*
* @param format framebuffer pixel formats are described using the fourcc codes defined in
* https://github.com/torvalds/linux/blob/master/include/uapi/drm/drm_fourcc.h
* @param width width of the requested buffer.
* @param height height of the requested buffer.
* @return true BufferObject creation was successful.
* @return false BufferObject creation was unsuccessful.
*/
virtual bool CreateBufferObject(uint32_t format, uint32_t width, uint32_t height) = 0;
/**
* @brief Create a BufferObject based only on the size of the desired buffer. Not all
* CBufferObject implementations may support this. This method is required for
* use with the CAddonVideoCodec as it only knows the decoded buffer size.
*
* @param size of the requested buffer.
* @return true BufferObject creation was successful.
* @return false BufferObject creation was unsuccessful.
*/
virtual bool CreateBufferObject(uint64_t size) = 0;
/**
* @brief Destroy a BufferObject.
*
*/
virtual void DestroyBufferObject() = 0;
/**
* @brief Get the Memory location of the BufferObject. This method needs to be
* called to be able to copy data into the BufferObject.
*
* @return uint8_t* pointer to the memory location of the BufferObject.
*/
virtual uint8_t *GetMemory() = 0;
/**
* @brief Release the mapped memory of the BufferObject. After calling this the memory
* location pointed to by GetMemory() will be invalid.
*
*/
virtual void ReleaseMemory() = 0;
/**
* @brief Get the File Descriptor of the BufferObject. The fd is guaranteed to be
* available after calling CreateBufferObject().
*
* @return int fd for the BufferObject. Invalid if -1.
*/
virtual int GetFd() = 0;
/**
* @brief Get the Stride of the BufferObject. The stride is guaranteed to be
* available after calling GetMemory().
*
* @return uint32_t stride of the BufferObject.
*/
virtual uint32_t GetStride() = 0;
/**
* @brief Get the Modifier of the BufferObject. Format Modifiers further describe
* the buffer's format such as for tiling or compression.
* see https://github.com/torvalds/linux/blob/master/include/uapi/drm/drm_fourcc.h
*
* @return uint64_t modifier of the BufferObject. 0 means the layout is linear (default).
*/
virtual uint64_t GetModifier() = 0;
/**
* @brief Must be called before reading/writing data to the BufferObject.
*
*/
virtual void SyncStart() = 0;
/**
* @brief Must be called after reading/writing data to the BufferObject.
*
*/
virtual void SyncEnd() = 0;
/**
* @brief Get the Name of the BufferObject type in use
*
* @return std::string name of the BufferObject type in use
*/
virtual std::string GetName() const = 0;
};
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