/*
 * Copyright 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @file hardware_buffer.h
 * @brief API for native hardware buffers.
 */
/**
 * @defgroup AHardwareBuffer Native Hardware Buffer
 *
 * AHardwareBuffer objects represent chunks of memory that can be
 * accessed by various hardware components in the system. It can be
 * easily converted to the Java counterpart
 * android.hardware.HardwareBuffer and passed between processes using
 * Binder. All operations involving AHardwareBuffer and HardwareBuffer
 * are zero-copy, i.e., passing AHardwareBuffer to another process
 * creates a shared view of the same region of memory.
 *
 * AHardwareBuffers can be bound to EGL/OpenGL and Vulkan primitives.
 * For EGL, use the extension function eglGetNativeClientBufferANDROID
 * to obtain an EGLClientBuffer and pass it directly to
 * eglCreateImageKHR. Refer to the EGL extensions
 * EGL_ANDROID_get_native_client_buffer and
 * EGL_ANDROID_image_native_buffer for more information. In Vulkan,
 * the contents of the AHardwareBuffer can be accessed as external
 * memory. See the VK_ANDROID_external_memory_android_hardware_buffer
 * extension for details.
 *
 * @{
 */

module android.ndk.hardware_buffer;

import arsd.jni;
import android.ndk;

extern (C):
nothrow:
@nogc:

/**
 * Buffer pixel formats.
 */
enum AHardwareBuffer_Format
{
    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_R8G8B8A8_UNORM
     *   OpenGL ES: GL_RGBA8
     */
    AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM = 1,

    /**
     * 32 bits per pixel, 8 bits per channel format where alpha values are
     * ignored (always opaque).
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_R8G8B8A8_UNORM
     *   OpenGL ES: GL_RGB8
     */
    AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM = 2,

    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_R8G8B8_UNORM
     *   OpenGL ES: GL_RGB8
     */
    AHARDWAREBUFFER_FORMAT_R8G8B8_UNORM = 3,

    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_R5G6B5_UNORM_PACK16
     *   OpenGL ES: GL_RGB565
     */
    AHARDWAREBUFFER_FORMAT_R5G6B5_UNORM = 4,

    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_R16G16B16A16_SFLOAT
     *   OpenGL ES: GL_RGBA16F
     */
    AHARDWAREBUFFER_FORMAT_R16G16B16A16_FLOAT = 0x16,

    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_A2B10G10R10_UNORM_PACK32
     *   OpenGL ES: GL_RGB10_A2
     */
    AHARDWAREBUFFER_FORMAT_R10G10B10A2_UNORM = 0x2b,

    /**
     * Opaque binary blob format.
     * Must have height 1 and one layer, with width equal to the buffer
     * size in bytes. Corresponds to Vulkan buffers and OpenGL buffer
     * objects. Can be bound to the latter using GL_EXT_external_buffer.
     */
    AHARDWAREBUFFER_FORMAT_BLOB = 0x21,

    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_D16_UNORM
     *   OpenGL ES: GL_DEPTH_COMPONENT16
     */
    AHARDWAREBUFFER_FORMAT_D16_UNORM = 0x30,

    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_X8_D24_UNORM_PACK32
     *   OpenGL ES: GL_DEPTH_COMPONENT24
     */
    AHARDWAREBUFFER_FORMAT_D24_UNORM = 0x31,

    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_D24_UNORM_S8_UINT
     *   OpenGL ES: GL_DEPTH24_STENCIL8
     */
    AHARDWAREBUFFER_FORMAT_D24_UNORM_S8_UINT = 0x32,

    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_D32_SFLOAT
     *   OpenGL ES: GL_DEPTH_COMPONENT32F
     */
    AHARDWAREBUFFER_FORMAT_D32_FLOAT = 0x33,

    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_D32_SFLOAT_S8_UINT
     *   OpenGL ES: GL_DEPTH32F_STENCIL8
     */
    AHARDWAREBUFFER_FORMAT_D32_FLOAT_S8_UINT = 0x34,

    /**
     * Corresponding formats:
     *   Vulkan: VK_FORMAT_S8_UINT
     *   OpenGL ES: GL_STENCIL_INDEX8
     */
    AHARDWAREBUFFER_FORMAT_S8_UINT = 0x35,

    /**
     * YUV 420 888 format.
     * Must have an even width and height. Can be accessed in OpenGL
     * shaders through an external sampler. Does not support mip-maps
     * cube-maps or multi-layered textures.
     */
    AHARDWAREBUFFER_FORMAT_Y8Cb8Cr8_420 = 0x23
}

/**
 * Buffer usage flags, specifying how the buffer will be accessed.
 */
enum AHardwareBuffer_UsageFlags
{
    /// The buffer will never be locked for direct CPU reads using the
    /// AHardwareBuffer_lock() function. Note that reading the buffer
    /// using OpenGL or Vulkan functions or memory mappings is still
    /// allowed.
    AHARDWAREBUFFER_USAGE_CPU_READ_NEVER = 0UL,
    /// The buffer will sometimes be locked for direct CPU reads using
    /// the AHardwareBuffer_lock() function. Note that reading the
    /// buffer using OpenGL or Vulkan functions or memory mappings
    /// does not require the presence of this flag.
    AHARDWAREBUFFER_USAGE_CPU_READ_RARELY = 2UL,
    /// The buffer will often be locked for direct CPU reads using
    /// the AHardwareBuffer_lock() function. Note that reading the
    /// buffer using OpenGL or Vulkan functions or memory mappings
    /// does not require the presence of this flag.
    AHARDWAREBUFFER_USAGE_CPU_READ_OFTEN = 3UL,
    /// CPU read value mask.
    AHARDWAREBUFFER_USAGE_CPU_READ_MASK = 0xFUL,

    /// The buffer will never be locked for direct CPU writes using the
    /// AHardwareBuffer_lock() function. Note that writing the buffer
    /// using OpenGL or Vulkan functions or memory mappings is still
    /// allowed.
    AHARDWAREBUFFER_USAGE_CPU_WRITE_NEVER = 0UL << 4,
    /// The buffer will sometimes be locked for direct CPU writes using
    /// the AHardwareBuffer_lock() function. Note that writing the
    /// buffer using OpenGL or Vulkan functions or memory mappings
    /// does not require the presence of this flag.
    AHARDWAREBUFFER_USAGE_CPU_WRITE_RARELY = 2UL << 4,
    /// The buffer will often be locked for direct CPU writes using
    /// the AHardwareBuffer_lock() function. Note that writing the
    /// buffer using OpenGL or Vulkan functions or memory mappings
    /// does not require the presence of this flag.
    AHARDWAREBUFFER_USAGE_CPU_WRITE_OFTEN = 3UL << 4,
    /// CPU write value mask.
    AHARDWAREBUFFER_USAGE_CPU_WRITE_MASK = 0xFUL << 4,

    /// The buffer will be read from by the GPU as a texture.
    AHARDWAREBUFFER_USAGE_GPU_SAMPLED_IMAGE = 1UL << 8,
    /// The buffer will be written to by the GPU as a framebuffer attachment.
    AHARDWAREBUFFER_USAGE_GPU_FRAMEBUFFER = 1UL << 9,
    /**
     * The buffer will be written to by the GPU as a framebuffer
     * attachment.
     *
     * Note that the name of this flag is somewhat misleading: it does
     * not imply that the buffer contains a color format. A buffer with
     * depth or stencil format that will be used as a framebuffer
     * attachment should also have this flag. Use the equivalent flag
     * AHARDWAREBUFFER_USAGE_GPU_FRAMEBUFFER to avoid this confusion.
     */
    AHARDWAREBUFFER_USAGE_GPU_COLOR_OUTPUT = AHARDWAREBUFFER_USAGE_GPU_FRAMEBUFFER,
    /**
     * The buffer will be used as a composer HAL overlay layer.
     *
     * This flag is currently only needed when using ASurfaceTransaction_setBuffer
     * to set a buffer. In all other cases, the framework adds this flag
     * internally to buffers that could be presented in a composer overlay.
     * ASurfaceTransaction_setBuffer is special because it uses buffers allocated
     * directly through AHardwareBuffer_allocate instead of buffers allocated
     * by the framework.
     */
    AHARDWAREBUFFER_USAGE_COMPOSER_OVERLAY = 1UL << 11,
    /**
     * The buffer is protected from direct CPU access or being read by
     * non-secure hardware, such as video encoders.
     *
     * This flag is incompatible with CPU read and write flags. It is
     * mainly used when handling DRM video. Refer to the EGL extension
     * EGL_EXT_protected_content and GL extension
     * GL_EXT_protected_textures for more information on how these
     * buffers are expected to behave.
     */
    AHARDWAREBUFFER_USAGE_PROTECTED_CONTENT = 1UL << 14,
    /// The buffer will be read by a hardware video encoder.
    AHARDWAREBUFFER_USAGE_VIDEO_ENCODE = 1UL << 16,
    /**
     * The buffer will be used for direct writes from sensors.
     * When this flag is present, the format must be AHARDWAREBUFFER_FORMAT_BLOB.
     */
    AHARDWAREBUFFER_USAGE_SENSOR_DIRECT_DATA = 1UL << 23,
    /**
     * The buffer will be used as a shader storage or uniform buffer object.
     * When this flag is present, the format must be AHARDWAREBUFFER_FORMAT_BLOB.
     */
    AHARDWAREBUFFER_USAGE_GPU_DATA_BUFFER = 1UL << 24,
    /**
     * The buffer will be used as a cube map texture.
     * When this flag is present, the buffer must have a layer count
     * that is a multiple of 6. Note that buffers with this flag must be
     * bound to OpenGL textures using the extension
     * GL_EXT_EGL_image_storage instead of GL_KHR_EGL_image.
     */
    AHARDWAREBUFFER_USAGE_GPU_CUBE_MAP = 1UL << 25,
    /**
     * The buffer contains a complete mipmap hierarchy.
     * Note that buffers with this flag must be bound to OpenGL textures using
     * the extension GL_EXT_EGL_image_storage instead of GL_KHR_EGL_image.
     */
    AHARDWAREBUFFER_USAGE_GPU_MIPMAP_COMPLETE = 1UL << 26,

    AHARDWAREBUFFER_USAGE_VENDOR_0 = 1UL << 28,
    AHARDWAREBUFFER_USAGE_VENDOR_1 = 1UL << 29,
    AHARDWAREBUFFER_USAGE_VENDOR_2 = 1UL << 30,
    AHARDWAREBUFFER_USAGE_VENDOR_3 = 1UL << 31,
    AHARDWAREBUFFER_USAGE_VENDOR_4 = 1UL << 48,
    AHARDWAREBUFFER_USAGE_VENDOR_5 = 1UL << 49,
    AHARDWAREBUFFER_USAGE_VENDOR_6 = 1UL << 50,
    AHARDWAREBUFFER_USAGE_VENDOR_7 = 1UL << 51,
    AHARDWAREBUFFER_USAGE_VENDOR_8 = 1UL << 52,
    AHARDWAREBUFFER_USAGE_VENDOR_9 = 1UL << 53,
    AHARDWAREBUFFER_USAGE_VENDOR_10 = 1UL << 54,
    AHARDWAREBUFFER_USAGE_VENDOR_11 = 1UL << 55,
    AHARDWAREBUFFER_USAGE_VENDOR_12 = 1UL << 56,
    AHARDWAREBUFFER_USAGE_VENDOR_13 = 1UL << 57,
    AHARDWAREBUFFER_USAGE_VENDOR_14 = 1UL << 58,
    AHARDWAREBUFFER_USAGE_VENDOR_15 = 1UL << 59,
    AHARDWAREBUFFER_USAGE_VENDOR_16 = 1UL << 60,
    AHARDWAREBUFFER_USAGE_VENDOR_17 = 1UL << 61,
    AHARDWAREBUFFER_USAGE_VENDOR_18 = 1UL << 62,
    AHARDWAREBUFFER_USAGE_VENDOR_19 = 1UL << 63
}

/**
 * Buffer description. Used for allocating new buffers and querying
 * parameters of existing ones.
 */
struct AHardwareBuffer_Desc
{
    uint width; ///< Width in pixels.
    uint height; ///< Height in pixels.
    /**
     * Number of images in an image array. AHardwareBuffers with one
     * layer correspond to regular 2D textures. AHardwareBuffers with
     * more than layer correspond to texture arrays. If the layer count
     * is a multiple of 6 and the usage flag
     * AHARDWAREBUFFER_USAGE_GPU_CUBE_MAP is present, the buffer is
     * a cube map or a cube map array.
     */
    uint layers;
    uint format; ///< One of AHardwareBuffer_Format.
    ulong usage; ///< Combination of AHardwareBuffer_UsageFlags.
    uint stride; ///< Row stride in pixels, ignored for AHardwareBuffer_allocate()
    uint rfu0; ///< Initialize to zero, reserved for future use.
    ulong rfu1; ///< Initialize to zero, reserved for future use.
}

/**
 * Holds data for a single image plane.
 */
struct AHardwareBuffer_Plane
{
    void* data; ///< Points to first byte in plane
    uint pixelStride; ///< Distance in bytes from the color channel of one pixel to the next
    uint rowStride; ///< Distance in bytes from the first value of one row of the image to
    ///  the first value of the next row.
}

/**
 * Holds all image planes that contain the pixel data.
 */
struct AHardwareBuffer_Planes
{
    uint planeCount; ///< Number of distinct planes
    AHardwareBuffer_Plane[4] planes; ///< Array of image planes
}

/**
 * Opaque handle for a native hardware buffer.
 */
struct AHardwareBuffer;

/**
 * Allocates a buffer that matches the passed AHardwareBuffer_Desc.
 *
 * If allocation succeeds, the buffer can be used according to the
 * usage flags specified in its description. If a buffer is used in ways
 * not compatible with its usage flags, the results are undefined and
 * may include program termination.
 *
 * \return 0 on success, or an error number of the allocation fails for
 * any reason. The returned buffer has a reference count of 1.
 */
int AHardwareBuffer_allocate (
    const(AHardwareBuffer_Desc)* desc,
    AHardwareBuffer** outBuffer);
/**
 * Acquire a reference on the given AHardwareBuffer object.
 *
 * This prevents the object from being deleted until the last reference
 * is removed.
 */
void AHardwareBuffer_acquire (AHardwareBuffer* buffer);

/**
 * Remove a reference that was previously acquired with
 * AHardwareBuffer_acquire() or AHardwareBuffer_allocate().
 */
void AHardwareBuffer_release (AHardwareBuffer* buffer);

/**
 * Return a description of the AHardwareBuffer in the passed
 * AHardwareBuffer_Desc struct.
 */
void AHardwareBuffer_describe (
    const(AHardwareBuffer)* buffer,
    AHardwareBuffer_Desc* outDesc);

/**
 * Lock the AHardwareBuffer for direct CPU access.
 *
 * This function can lock the buffer for either reading or writing.
 * It may block if the hardware needs to finish rendering, if CPU caches
 * need to be synchronized, or possibly for other implementation-
 * specific reasons.
 *
 * The passed AHardwareBuffer must have one layer, otherwise the call
 * will fail.
 *
 * If \a fence is not negative, it specifies a fence file descriptor on
 * which to wait before locking the buffer. If it's negative, the caller
 * is responsible for ensuring that writes to the buffer have completed
 * before calling this function.  Using this parameter is more efficient
 * than waiting on the fence and then calling this function.
 *
 * The \a usage parameter may only specify AHARDWAREBUFFER_USAGE_CPU_*.
 * If set, then outVirtualAddress is filled with the address of the
 * buffer in virtual memory. The flags must also be compatible with
 * usage flags specified at buffer creation: if a read flag is passed,
 * the buffer must have been created with
 * AHARDWAREBUFFER_USAGE_CPU_READ_RARELY or
 * AHARDWAREBUFFER_USAGE_CPU_READ_OFTEN. If a write flag is passed, it
 * must have been created with AHARDWAREBUFFER_USAGE_CPU_WRITE_RARELY or
 * AHARDWAREBUFFER_USAGE_CPU_WRITE_OFTEN.
 *
 * If \a rect is not NUL, the caller promises to modify only data in
 * the area specified by rect. If rect is NUL, the caller may modify
 * the contents of the entire buffer. The content of the buffer outside
 * of the specified rect is NOT modified by this call.
 *
 * It is legal for several different threads to lock a buffer for read
 * access; none of the threads are blocked.
 *
 * Locking a buffer simultaneously for write or read/write is undefined,
 * but will neither terminate the process nor block the caller.
 * AHardwareBuffer_lock may return an error or leave the buffer's
 * content in an indeterminate state.
 *
 * If the buffer has AHARDWAREBUFFER_FORMAT_BLOB, it is legal lock it
 * for reading and writing in multiple threads and/or processes
 * simultaneously, and the contents of the buffer behave like shared
 * memory.
 *
 * \return 0 on success. -EINVAL if \a buffer is NUL, the usage flags
 * are not a combination of AHARDWAREBUFFER_USAGE_CPU_*, or the buffer
 * has more than one layer. Error number if the lock fails for any other
 * reason.
 */
int AHardwareBuffer_lock (
    AHardwareBuffer* buffer,
    ulong usage,
    int fence,
    const(ARect)* rect,
    void** outVirtualAddress);

/**
 * Lock a potentially multi-planar AHardwareBuffer for direct CPU access.
 *
 * This function is similar to AHardwareBuffer_lock, but can lock multi-planar
 * formats. The locked planes are returned in the \a outPlanes argument. Note,
 * that multi-planar should not be confused with multi-layer images, which this
 * locking function does not support.
 *
 * YUV formats are always represented by three separate planes of data, one for
 * each color plane. The order of planes in the array is guaranteed such that
 * plane #0 is always Y, plane #1 is always U (Cb), and plane #2 is always V
 * (Cr). All other formats are represented by a single plane.
 *
 * Additional information always accompanies the buffers, describing the row
 * stride and the pixel stride for each plane.
 *
 * In case the buffer cannot be locked, \a outPlanes will contain zero planes.
 *
 * See the AHardwareBuffer_lock documentation for all other locking semantics.
 *
 * \return 0 on success. -EINVAL if \a buffer is NUL, the usage flags
 * are not a combination of AHARDWAREBUFFER_USAGE_CPU_*, or the buffer
 * has more than one layer. Error number if the lock fails for any other
 * reason.
 */
int AHardwareBuffer_lockPlanes (
    AHardwareBuffer* buffer,
    ulong usage,
    int fence,
    const(ARect)* rect,
    AHardwareBuffer_Planes* outPlanes);

/**
 * Unlock the AHardwareBuffer from direct CPU access.
 *
 * Must be called after all changes to the buffer are completed by the
 * caller.  If \a fence is NUL, the function will block until all work
 * is completed.  Otherwise, \a fence will be set either to a valid file
 * descriptor or to -1.  The file descriptor will become signaled once
 * the unlocking is complete and buffer contents are updated.
 * The caller is responsible for closing the file descriptor once it's
 * no longer needed.  The value -1 indicates that unlocking has already
 * completed before the function returned and no further operations are
 * necessary.
 *
 * \return 0 on success. -EINVAL if \a buffer is NUL. Error number if
 * the unlock fails for any reason.
 */
int AHardwareBuffer_unlock (AHardwareBuffer* buffer, int* fence);

/**
 * Send the AHardwareBuffer to an AF_UNIX socket.
 *
 * \return 0 on success, -EINVAL if \a buffer is NUL, or an error
 * number if the operation fails for any reason.
 */
int AHardwareBuffer_sendHandleToUnixSocket (const(AHardwareBuffer)* buffer, int socketFd);

/**
 * Receive an AHardwareBuffer from an AF_UNIX socket.
 *
 * \return 0 on success, -EINVAL if \a outBuffer is NUL, or an error
 * number if the operation fails for any reason.
 */
int AHardwareBuffer_recvHandleFromUnixSocket (int socketFd, AHardwareBuffer** outBuffer);

// __ANDROID_API__ >= 26

/**
 * Test whether the given format and usage flag combination is
 * allocatable.
 *
 * If this function returns true, it means that a buffer with the given
 * description can be allocated on this implementation, unless resource
 * exhaustion occurs. If this function returns false, it means that the
 * allocation of the given description will never succeed.
 *
 * The return value of this function may depend on all fields in the
 * description, except stride, which is always ignored. For example,
 * some implementations have implementation-defined limits on texture
 * size and layer count.
 *
 * \return 1 if the format and usage flag combination is allocatable,
 *     0 otherwise.
 */
int AHardwareBuffer_isSupported (const(AHardwareBuffer_Desc)* desc);

/**
 * Lock an AHardwareBuffer for direct CPU access.
 *
 * This function is the same as the above lock function, but passes back
 * additional information about the bytes per pixel and the bytes per stride
 * of the locked buffer.  If the bytes per pixel or bytes per stride are unknown
 * or variable, or if the underlying mapper implementation does not support returning
 * additional information, then this call will fail with INVALID_OPERATION
 */
int AHardwareBuffer_lockAndGetInfo (
    AHardwareBuffer* buffer,
    ulong usage,
    int fence,
    const(ARect)* rect,
    void** outVirtualAddress,
    int* outBytesPerPixel,
    int* outBytesPerStride);
// __ANDROID_API__ >= 29

// ANDROID_HARDWARE_BUFFER_H

/** @} */