path: root/src/H5Tref.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Module Info: This module contains the functionality for reference
 *      datatypes in the H5T interface.
 */

#include "H5Tmodule.h"          /* This source code file is part of the H5T module */
#define H5F_FRIEND              /*suppress error about including H5Fpkg   */
#define H5R_FRIEND              /*suppress error about including H5Rpkg   */

#include "H5private.h"          /* Generic Functions    */
#include "H5CXprivate.h"        /* API Contexts         */
#include "H5Eprivate.h"         /* Error handling       */
#include "H5Iprivate.h"         /* IDs                  */
#include "H5Fpkg.h"             /* File                 */
#include "H5Rpkg.h"             /* References           */
#include "H5Tpkg.h"             /* Datatypes            */

#include "H5VLnative_private.h" /* Native VOL connector                     */

/****************/
/* Local Macros */
/****************/

#define H5T_REF_MEM_SIZE                (H5R_REF_BUF_SIZE)
#define H5T_REF_OBJ_MEM_SIZE            (H5R_OBJ_REF_BUF_SIZE)
#define H5T_REF_DSETREG_MEM_SIZE        (H5R_DSET_REG_REF_BUF_SIZE)

#define H5T_REF_OBJ_DISK_SIZE(f)        (H5F_SIZEOF_ADDR(f))
#define H5T_REF_DSETREG_DISK_SIZE(f)    (H5HG_HEAP_ID_SIZE(f))

/******************/
/* Local Typedefs */
/******************/

/* For region compatibility support */
struct H5Tref_dsetreg {
    H5VL_token_t token; /* Object token */
    H5S_t *space;       /* Dataspace */
};

/********************/
/* Local Prototypes */
/********************/

static herr_t H5T__ref_mem_isnull(const H5VL_object_t *src_file, const void *src_buf, hbool_t *isnull);
static herr_t H5T__ref_mem_setnull(H5VL_object_t *dst_file, void *dst_buf, void *bg_buf);
static size_t H5T__ref_mem_getsize(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, hbool_t *dst_copy);
static herr_t H5T__ref_mem_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size);
static herr_t H5T__ref_mem_write(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5R_type_t src_type, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size, void *bg_buf);

static herr_t H5T__ref_disk_isnull(const H5VL_object_t *src_file, const void *src_buf, hbool_t *isnull);
static herr_t H5T__ref_disk_setnull(H5VL_object_t *dst_file, void *dst_buf, void *bg_buf);
static size_t H5T__ref_disk_getsize(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, hbool_t *dst_copy);
static herr_t H5T__ref_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size);
static herr_t H5T__ref_disk_write(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5R_type_t src_type, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size, void *bg_buf);

/* For compatibility */
static herr_t H5T__ref_obj_disk_isnull(const H5VL_object_t *src_file, const void *src_buf, hbool_t *isnull);
static size_t H5T__ref_obj_disk_getsize(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, hbool_t *dst_copy);
static herr_t H5T__ref_obj_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size);

static herr_t H5T__ref_dsetreg_disk_isnull(const H5VL_object_t *src_file, const void *src_buf, hbool_t *isnull);
static size_t H5T__ref_dsetreg_disk_getsize(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, hbool_t *dst_copy);
static herr_t H5T__ref_dsetreg_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size);

/*******************/
/* Local Variables */
/*******************/

/* Class for reference in memory */
static const H5T_ref_class_t H5T_ref_mem_g = {
    H5T__ref_mem_isnull,            /* 'isnull' */
    H5T__ref_mem_setnull,           /* 'setnull' */
    H5T__ref_mem_getsize,           /* 'getsize' */
    H5T__ref_mem_read,              /* 'read' */
    H5T__ref_mem_write              /* 'write' */
};

static const H5T_ref_class_t H5T_ref_disk_g = {
    H5T__ref_disk_isnull,           /* 'isnull' */
    H5T__ref_disk_setnull,          /* 'setnull' */
    H5T__ref_disk_getsize,          /* 'getsize' */
    H5T__ref_disk_read,             /* 'read' */
    H5T__ref_disk_write             /* 'write' */
};

static const H5T_ref_class_t H5T_ref_obj_disk_g = {
    H5T__ref_obj_disk_isnull,       /* 'isnull' */
    NULL,                           /* 'setnull' */
    H5T__ref_obj_disk_getsize,      /* 'getsize' */
    H5T__ref_obj_disk_read,         /* 'read' */
    NULL                            /* 'write' */
};

static const H5T_ref_class_t H5T_ref_dsetreg_disk_g = {
    H5T__ref_dsetreg_disk_isnull,   /* 'isnull' */
    NULL,                           /* 'setnull' */
    H5T__ref_dsetreg_disk_getsize,  /* 'getsize' */
    H5T__ref_dsetreg_disk_read,     /* 'read' */
    NULL                            /* 'write' */
};


/*-------------------------------------------------------------------------
 * Function: H5T__ref_set_loc
 *
 * Purpose:	Sets the location of a reference datatype to be either on disk
 *          or in memory
 *
 * Return:
 *  One of two values on success:
 *      TRUE - If the location of any reference types changed
 *      FALSE - If the location of any reference types is the same
 *  Negative value is returned on failure
 *
 *-------------------------------------------------------------------------
 */
htri_t
H5T__ref_set_loc(const H5T_t *dt, H5VL_object_t *file, H5T_loc_t loc)
{
    htri_t ret_value = FALSE; /* Indicate success, but no location change */

    FUNC_ENTER_PACKAGE

    HDassert(dt);
    /* f is NULL when loc == H5T_LOC_MEMORY */
    HDassert(loc >= H5T_LOC_BADLOC && loc < H5T_LOC_MAXLOC);

    /* Only change the location if it's different */
    if(loc == dt->shared->u.atomic.u.r.loc && file == dt->shared->u.atomic.u.r.file)
        HGOTO_DONE(FALSE)

    switch(loc) {
        case H5T_LOC_MEMORY: /* Memory based reference datatype */
            HDassert(NULL == file);

            /* Mark this type as being stored in memory */
            dt->shared->u.atomic.u.r.loc = H5T_LOC_MEMORY;

            /* Reset file ID (since this reference is in memory) */
            dt->shared->u.atomic.u.r.file = file;     /* file is NULL */

            if(dt->shared->u.atomic.u.r.opaque) {
                /* Size in memory, disk size is different */
                dt->shared->size = H5T_REF_MEM_SIZE;
                dt->shared->u.atomic.prec = 8 * dt->shared->size;

                /* Set up the function pointers to access the reference in memory */
                dt->shared->u.atomic.u.r.cls = &H5T_ref_mem_g;

            } else if(dt->shared->u.atomic.u.r.rtype == H5R_OBJECT1) {
                /* Size in memory, disk size is different */
                dt->shared->size = H5T_REF_OBJ_MEM_SIZE;
                dt->shared->u.atomic.prec = 8 * dt->shared->size;

                /* Unused for now */
                dt->shared->u.atomic.u.r.cls = NULL;

            } else if(dt->shared->u.atomic.u.r.rtype == H5R_DATASET_REGION1) {
                /* Size in memory, disk size is different */
                dt->shared->size = H5T_REF_DSETREG_MEM_SIZE;
                dt->shared->u.atomic.prec = 8 * dt->shared->size;

                /* Unused for now */
                dt->shared->u.atomic.u.r.cls = NULL;

            }
            break;

        case H5T_LOC_DISK: /* Disk based reference datatype */
            HDassert(file);

            /* Mark this type as being stored on disk */
            dt->shared->u.atomic.u.r.loc = H5T_LOC_DISK;

            /* Set file pointer (since this reference is on disk) */
            dt->shared->u.atomic.u.r.file = file;

            if(dt->shared->u.atomic.u.r.rtype == H5R_OBJECT1) {
                H5F_t *f;

                /* We should assert here that the terminal connector is H5VL_NATIVE once
                 * there is a facility to do so -NAF 2019/10/30 */

                /* Retrieve file from VOL object */
                if(NULL == (f = (H5F_t *)H5VL_object_data(file)))
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid VOL object")

                /* Size on disk, memory size is different */
                dt->shared->size = H5T_REF_OBJ_DISK_SIZE(f);
                dt->shared->u.atomic.prec = 8 * dt->shared->size;

                /* Set up the function pointers to access the reference in memory */
                dt->shared->u.atomic.u.r.cls = &H5T_ref_obj_disk_g;

            } else if(dt->shared->u.atomic.u.r.rtype == H5R_DATASET_REGION1) {
                H5F_t *f;

                /* We should assert here that the terminal connector is H5VL_NATIVE once
                 * there is a facility to do so -NAF 2019/10/30 */

                /* Retrieve file from VOL object */
                if(NULL == (f = (H5F_t *)H5VL_object_data(file)))
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid VOL object")

                /* Size on disk, memory size is different */
                dt->shared->size = H5T_REF_DSETREG_DISK_SIZE(f);
                dt->shared->u.atomic.prec = 8 * dt->shared->size;

                /* Set up the function pointers to access the reference in memory */
                dt->shared->u.atomic.u.r.cls = &H5T_ref_dsetreg_disk_g;

            } else {
                H5VL_file_cont_info_t cont_info = {H5VL_CONTAINER_INFO_VERSION, 0, 0, 0};
                size_t ref_encode_size;
                H5R_ref_priv_t fixed_ref;

                /* Get container info */
                if(H5VL_file_get(file, H5VL_FILE_GET_CONT_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &cont_info) < 0)
                    HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "unable to get container info")

                /* Retrieve min encode size (when references have no vlen part) */
                HDmemset(&fixed_ref, 0, sizeof(fixed_ref));
                fixed_ref.type = (int8_t)H5R_OBJECT2;
                fixed_ref.token_size = (uint8_t)cont_info.token_size;
                if(H5R__encode(NULL, &fixed_ref, NULL, &ref_encode_size, 0) < 0)
                    HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "can't get encode size")

                /* Size on disk, memory size is different */
                dt->shared->size = MAX(H5_SIZEOF_UINT32_T +
                    H5R_ENCODE_HEADER_SIZE + cont_info.blob_id_size,
                    ref_encode_size);
                dt->shared->u.atomic.prec = 8 * dt->shared->size;

                /* Set up the function pointers to access the information on
                 * disk. Region and attribute references are stored identically
                 * on disk, so use the same functions.
                 */
                dt->shared->u.atomic.u.r.cls = &H5T_ref_disk_g;

            }
            break;

        case H5T_LOC_BADLOC:
            /* Allow undefined location. In H5Odtype.c, H5O_dtype_decode sets undefined
             * location for reference type and leaves it for the caller to decide.
             */
            dt->shared->u.atomic.u.r.loc = H5T_LOC_BADLOC;

            /* Reset file pointer */
            dt->shared->u.atomic.u.r.file = NULL;

            /* Reset the function pointers */
            dt->shared->u.atomic.u.r.cls = NULL;

            break;

        case H5T_LOC_MAXLOC:
            /* MAXLOC is invalid */
        default:
            HGOTO_ERROR(H5E_DATATYPE, H5E_BADRANGE, FAIL, "invalid reference datatype location")
    } /* end switch */

    /* Indicate that the location changed */
    ret_value = TRUE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_set_loc() */


/*-------------------------------------------------------------------------
 * Function:    H5T__ref_mem_isnull
 *
 * Purpose: Check if it's a NULL / uninitialized reference.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_mem_isnull(const H5VL_object_t H5_ATTR_UNUSED *src_file,
    const void *src_buf, hbool_t *isnull)
{
    const unsigned char zeros[H5T_REF_MEM_SIZE] = { 0 };
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC_NOERR

    /* Check parameters */
    HDassert(src_buf);
    HDassert(isnull);

    *isnull = (0 == HDmemcmp(src_buf, zeros, H5T_REF_MEM_SIZE)) ? TRUE : FALSE;

    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_mem_isnull() */


/*-------------------------------------------------------------------------
 * Function:    H5T__ref_mem_setnull
 *
 * Purpose: Set a reference as NULL / uninitialized.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_mem_setnull(H5VL_object_t H5_ATTR_UNUSED *dst_file, void *dst_buf,
    H5_ATTR_UNUSED void *bg_buf)
{
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC_NOERR

    HDmemset(dst_buf, 0, H5T_REF_MEM_SIZE);

    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_mem_setnull() */


/*-------------------------------------------------------------------------
 * Function:	H5T__ref_mem_getsize
 *
 * Purpose:	Retrieves the size of a memory based reference.
 *
 * Return:	Non-negative on success/zero on failure
 *
 *-------------------------------------------------------------------------
 */
static size_t
H5T__ref_mem_getsize(H5VL_object_t H5_ATTR_UNUSED *src_file, const void *src_buf,
    size_t H5_ATTR_UNUSED src_size, H5VL_object_t *dst_file, hbool_t *dst_copy)
{
    H5VL_object_t *vol_obj = NULL;
    const H5R_ref_priv_t *src_ref = (const H5R_ref_priv_t *)src_buf;
    hbool_t files_equal = FALSE;
    char file_name_buf_static[256];
    char *file_name_buf_dyn = NULL;
    ssize_t file_name_len;
    unsigned flags = 0;
    size_t ret_value = 0;

    FUNC_ENTER_STATIC

    HDassert(src_buf);
    HDassert(src_size == H5T_REF_MEM_SIZE);

    /* Retrieve VOL object */
    if(NULL == (vol_obj = H5VL_vol_object(src_ref->loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, 0, "invalid location identifier")

    /* Set external flag if referenced file is not destination file */
    if(H5VL_file_specific(vol_obj, H5VL_FILE_IS_EQUAL, H5P_DATASET_XFER_DEFAULT, NULL, dst_file, &files_equal) < 0)
        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCOMPARE, 0, "can't check if files are equal")
    flags |= !files_equal ? H5R_IS_EXTERNAL : 0;

    /* Force re-calculating encoding size if any flags are set */
    if(flags || !src_ref->encode_size) {
        /* Pass the correct encoding version for the selection depending on the
         * file libver bounds, this is later retrieved in H5S hyper encode */
        if(src_ref->type == (int8_t)H5R_DATASET_REGION2) {
            /* Temporary hack to check if this is the native connector.  We need to
             * add a way to check if the terminal connector is native.  For now this
             * will break passthroughs, but it's needed for other VOL connectors to
             * work.  -NAF */
            if(dst_file->connector->cls->value == H5VL_NATIVE_VALUE) {
                H5F_t *dst_f;

                if(NULL == (dst_f = (H5F_t *)H5VL_object_data(dst_file)))
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, 0, "invalid VOL object")
                H5CX_set_libver_bounds(dst_f);
            } /* end if */
            else
                H5CX_set_libver_bounds(NULL);
        } /* end if */

        /* Get file name */
        if(H5VL_file_get(vol_obj, H5VL_FILE_GET_NAME, H5P_DATASET_XFER_DEFAULT, NULL, H5I_FILE, sizeof(file_name_buf_static), file_name_buf_static, &file_name_len) < 0)
            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, 0, "can't get file name")
        if(file_name_len >= (ssize_t)sizeof(file_name_buf_static)) {
            if(NULL == (file_name_buf_dyn = (char *)H5MM_malloc((size_t)file_name_len + 1)))
                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, 0, "can't allocate space for file name")
            if(H5VL_file_get(vol_obj, H5VL_FILE_GET_NAME, H5P_DATASET_XFER_DEFAULT, NULL, H5I_FILE, (size_t)file_name_len + 1, file_name_buf_dyn, &file_name_len) < 0)
                HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, 0, "can't get file name")
        } /* end if */

        /* Determine encoding size */
        if(H5R__encode(file_name_buf_dyn ? file_name_buf_dyn : file_name_buf_static, src_ref, NULL, &ret_value, flags) < 0)
            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTENCODE, 0, "unable to determine encoding size")
    } else {
        /* Can do a direct copy and skip blob decoding */
        if(src_ref->type == (int8_t)H5R_OBJECT2)
            *dst_copy = TRUE;

        /* Get cached encoding size */
        ret_value = src_ref->encode_size;
    }

done:
    H5MM_xfree(file_name_buf_dyn);

    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_mem_getsize() */


/*-------------------------------------------------------------------------
 * Function:	H5T__ref_mem_read
 *
 * Purpose:	"Reads" the memory based reference into a buffer
 *
 * Return:	Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_mem_read(H5VL_object_t H5_ATTR_UNUSED *src_file, const void *src_buf,
    size_t H5_ATTR_UNUSED src_size, H5VL_object_t *dst_file, void *dst_buf,
    size_t dst_size)
{
    H5VL_object_t *vol_obj = NULL;
    const H5R_ref_priv_t *src_ref = (const H5R_ref_priv_t *)src_buf;
    hbool_t files_equal = FALSE;
    char file_name_buf_static[256];
    char *file_name_buf_dyn = NULL;
    ssize_t file_name_len;
    unsigned flags = 0;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    HDassert(src_buf);
    HDassert(src_size == H5T_REF_MEM_SIZE);
    HDassert(dst_file);
    HDassert(dst_buf);
    HDassert(dst_size);

    /* Retrieve VOL object */
    if(NULL == (vol_obj = H5VL_vol_object(src_ref->loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, 0, "invalid location identifier")

    /* Set external flag if referenced file is not destination file */
    if(H5VL_file_specific(vol_obj, H5VL_FILE_IS_EQUAL, H5P_DATASET_XFER_DEFAULT, NULL, dst_file, &files_equal) < 0)
        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCOMPARE, FAIL, "can't check if files are equal")
    flags |= !files_equal ? H5R_IS_EXTERNAL : 0;

    /* Pass the correct encoding version for the selection depending on the
     * file libver bounds, this is later retrieved in H5S hyper encode */
    if(src_ref->type == (int8_t)H5R_DATASET_REGION2) {
        /* Temporary hack to check if this is the native connector.  We need to
         * add a way to check if the terminal connector is native.  For now this
         * will break passthroughs, but it's needed for other VOL connectors to
         * work.  -NAF */
        if(dst_file->connector->cls->value == H5VL_NATIVE_VALUE) {
            H5F_t *dst_f;

            if(NULL == (dst_f = (H5F_t *)H5VL_object_data(dst_file)))
                HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, 0, "invalid VOL object")
            H5CX_set_libver_bounds(dst_f);
        } /* end if */
        else
            H5CX_set_libver_bounds(NULL);
    } /* end if */

    /* Get file name */
    if(H5VL_file_get(vol_obj, H5VL_FILE_GET_NAME, H5P_DATASET_XFER_DEFAULT, NULL, H5I_FILE, sizeof(file_name_buf_static), file_name_buf_static, &file_name_len) < 0)
        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, 0, "can't get file name")
    if(file_name_len >= (ssize_t)sizeof(file_name_buf_static)) {
        if(NULL == (file_name_buf_dyn = (char *)H5MM_malloc((size_t)file_name_len + 1)))
            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, 0, "can't allocate space for file name")
        if(H5VL_file_get(vol_obj, H5VL_FILE_GET_NAME, H5P_DATASET_XFER_DEFAULT, NULL, H5I_FILE, (size_t)file_name_len + 1, file_name_buf_dyn, &file_name_len) < 0)
            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, 0, "can't get file name")
    } /* end if */

    /* Encode reference */
    if(H5R__encode(file_name_buf_dyn ? file_name_buf_dyn : file_name_buf_static, src_ref, (unsigned char *)dst_buf, &dst_size, flags) < 0)
        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTENCODE, FAIL, "Cannot encode reference")

done:
    H5MM_xfree(file_name_buf_dyn);

    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_mem_read() */


/*-------------------------------------------------------------------------
 * Function:	H5T__ref_mem_write
 *
 * Purpose:	"Writes" the memory reference from a buffer
 *
 * Return:	Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_mem_write(H5VL_object_t *src_file, const void *src_buf, size_t src_size,
    H5R_type_t src_type, H5VL_object_t H5_ATTR_UNUSED *dst_file, void *dst_buf,
    size_t dst_size, void H5_ATTR_UNUSED *bg_buf)
{
    H5F_t *src_f;
    hid_t file_id = H5I_INVALID_HID;
    H5R_ref_priv_t *dst_ref = (H5R_ref_priv_t *)dst_buf;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    HDassert(src_file);
    HDassert(src_buf);
    HDassert(src_size);
    HDassert(dst_buf);
    HDassert(dst_size == H5T_REF_MEM_SIZE);

    /* We should assert here that the terminal connector is H5VL_NATIVE once
     * there is a facility to do so -NAF 2019/10/30 */

    /* Retrieve file from VOL object */
    if(NULL == (src_f = (H5F_t *)H5VL_object_data(src_file)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid VOL object")

    /* Make sure reference buffer is correctly initialized */
    HDmemset(dst_buf, 0, dst_size);

    switch(src_type) {
        case H5R_OBJECT1: {
            size_t token_size = H5F_SIZEOF_ADDR(src_f);

            if(H5R__create_object((const H5VL_token_t *)src_buf, token_size, dst_ref) < 0)
                HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCREATE, FAIL, "unable to create object reference")
        }
            break;
        case H5R_DATASET_REGION1: {
            const struct H5Tref_dsetreg *src_reg = (const struct H5Tref_dsetreg *)src_buf;
            size_t token_size = H5F_SIZEOF_ADDR(src_f);

            if(H5R__create_region(&src_reg->token, token_size, src_reg->space, dst_ref) < 0)
                HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCREATE, FAIL, "unable to create region reference")
            /* create_region creates its internal copy of the space */
            if(H5S_close(src_reg->space) < 0)
                HGOTO_ERROR(H5E_REFERENCE, H5E_CANTFREE, FAIL, "Cannot close dataspace")
        }
            break;
        case H5R_DATASET_REGION2:
            /* Pass the correct encoding version for the selection depending on the
             * file libver bounds, this is later retrieved in H5S hyper decode */
            H5CX_set_libver_bounds(src_f);
            H5_ATTR_FALLTHROUGH
        case H5R_OBJECT2:
        case H5R_ATTR:
            /* Decode reference */
            if(H5R__decode((const unsigned char *)src_buf, &src_size, dst_ref) < 0)
                HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, FAIL, "Cannot decode reference")
            break;
        case H5R_BADTYPE:
        case H5R_MAXTYPE:
        default:
            HDassert("unknown reference type" && 0);
            HGOTO_ERROR(H5E_REFERENCE, H5E_UNSUPPORTED, FAIL, "internal error (unknown reference type)")
    }

    /* If no filename set, this is not an external reference */
    if(NULL == H5R_REF_FILENAME(dst_ref)) {
        /* TODO temporary hack to retrieve file object */
        if((file_id = H5F_get_file_id(src_file, H5I_FILE, FALSE)) < 0)
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")

        /* Attach loc ID to reference and hold reference to it */
        if(H5R__set_loc_id(dst_ref, file_id, TRUE) < 0)
            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTSET, FAIL, "unable to attach location id to reference")
    }

done:
    if((file_id != H5I_INVALID_HID) && (H5I_dec_ref(file_id) < 0))
        HDONE_ERROR(H5E_REFERENCE, H5E_CANTDEC, FAIL, "unable to decrement refcount on location id")
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_mem_write() */


/*-------------------------------------------------------------------------
 * Function:    H5T__ref_disk_isnull
 *
 * Purpose: Check if it's a NULL / uninitialized reference.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_disk_isnull(const H5VL_object_t *src_file, const void *src_buf,
    hbool_t *isnull)
{
    const uint8_t *p = (const uint8_t *)src_buf;
    H5R_type_t ref_type;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    /* Check parameters */
    HDassert(src_file);
    HDassert(src_buf);
    HDassert(isnull);

    /* Try to check encoded reference type */
    ref_type = (H5R_type_t)*p++;
    if(ref_type) {
        /* This is a valid reference */
        *isnull = FALSE;
    } else {
        /* Skip the size / header */
        p = (const uint8_t *)src_buf + H5R_ENCODE_HEADER_SIZE + H5_SIZEOF_UINT32_T;

        /* Check if blob ID is "nil" */
        if(H5VL_blob_specific(src_file, (void *)p, H5VL_BLOB_ISNULL, isnull) < 0)
            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "unable to check if a blob ID is 'nil'")
    }

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_disk_isnull() */


/*-------------------------------------------------------------------------
 * Function:    H5T__ref_disk_setnull
 *
 * Purpose: Set a reference as NULL / uninitialized.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_disk_setnull(H5VL_object_t *dst_file, void *dst_buf, void *bg_buf)
{
    uint8_t *q = (uint8_t *)dst_buf;
    uint8_t *p_bg = (uint8_t *)bg_buf;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    HDassert(dst_file);
    HDassert(dst_buf);

    /* TODO Should get rid of bg stuff */
    if(p_bg) {
        /* Skip the size / header */
        p_bg += (H5_SIZEOF_UINT32_T + H5R_ENCODE_HEADER_SIZE);

        /* Remove blob for old data */
        if(H5VL_blob_specific(dst_file, (void *)p_bg, H5VL_BLOB_DELETE) < 0)
            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREMOVE, FAIL, "unable to delete blob")
    } /* end if */

    /* Copy header manually so that it does not get encoded into the blob */
    HDmemset(q, 0, H5R_ENCODE_HEADER_SIZE);
    q += H5R_ENCODE_HEADER_SIZE;

    /* Set the size */
    UINT32ENCODE(q, 0);

    /* Set blob ID to "nil" */
    if(H5VL_blob_specific(dst_file, q, H5VL_BLOB_SETNULL) < 0)
        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "unable to set a blob ID to 'nil'")

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_disk_setnull() */


/*-------------------------------------------------------------------------
 * Function:	H5T__ref_disk_getsize
 *
 * Purpose:	Retrieves the length of a disk based reference.
 *
 * Return:	Non-negative value (cannot fail)
 *
 *-------------------------------------------------------------------------
 */
static size_t
H5T__ref_disk_getsize(H5VL_object_t H5_ATTR_UNUSED *src_file, const void *src_buf,
    size_t src_size, H5VL_object_t H5_ATTR_UNUSED *dst_file, hbool_t *dst_copy)
{
    const uint8_t *p = (const uint8_t *)src_buf;
    unsigned flags;
    H5R_type_t ref_type;
    size_t ret_value = 0;

    FUNC_ENTER_STATIC

    HDassert(src_buf);

    /* Set reference type */
    ref_type = (H5R_type_t)*p++;
    if(ref_type <= H5R_BADTYPE || ref_type >= H5R_MAXTYPE)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, 0, "invalid reference type")

    /* Set flags */
    flags = (unsigned)*p++;

    if(!(flags & H5R_IS_EXTERNAL) && (ref_type == H5R_OBJECT2)) {
        /* Can do a direct copy and skip blob decoding */
        *dst_copy = TRUE;

        ret_value = src_size;
    } else {
        /* Retrieve encoded data size */
        UINT32DECODE(p, ret_value);

        /* Add size of the header */
        ret_value += H5R_ENCODE_HEADER_SIZE;
    }

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_disk_getsize() */


/*-------------------------------------------------------------------------
 * Function:	H5T__ref_disk_read
 *
 * Purpose:	Reads the disk based reference into a buffer
 *
 * Return:	Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t H5_ATTR_SANITY_CHECK src_size,
    H5VL_object_t H5_ATTR_UNUSED *dst_file, void *dst_buf, size_t dst_size)
{
    const uint8_t *p = (const uint8_t *)src_buf;
    uint8_t *q = (uint8_t *)dst_buf;
    size_t blob_size = dst_size;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    HDassert(src_file);
    HDassert(src_buf);
    HDassert(dst_buf);
    HDassert(dst_size);

    /* Copy header manually */
    HDmemcpy(q, p, H5R_ENCODE_HEADER_SIZE);
    p += H5R_ENCODE_HEADER_SIZE;
    q += H5R_ENCODE_HEADER_SIZE;
    blob_size -= H5R_ENCODE_HEADER_SIZE;

    /* Skip the size */
    p += H5_SIZEOF_UINT32_T;
    HDassert(src_size > (H5R_ENCODE_HEADER_SIZE + H5_SIZEOF_UINT32_T));

    /* Retrieve blob */
    if(H5VL_blob_get(src_file, p, q, blob_size, NULL) < 0)
        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "unable to get blob")

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_disk_read() */


/*-------------------------------------------------------------------------
 * Function:	H5T__ref_disk_write
 *
 * Purpose:	Writes the disk based reference from a buffer
 *
 * Return:	Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_disk_write(H5VL_object_t H5_ATTR_UNUSED *src_file, const void *src_buf,
    size_t src_size, H5R_type_t H5_ATTR_UNUSED src_type, H5VL_object_t *dst_file,
    void *dst_buf, size_t dst_size, void *bg_buf)
{
    const uint8_t *p = (const uint8_t *)src_buf;
    uint8_t *q = (uint8_t *)dst_buf;
    size_t buf_size_left = dst_size;
    uint8_t *p_bg = (uint8_t *)bg_buf;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    HDassert(src_buf);
    HDassert(src_size);
    HDassert(dst_file);
    HDassert(dst_buf);

    /* TODO Should get rid of bg stuff */
    if(p_bg) {
        size_t p_buf_size_left = dst_size;

        /* Skip the size / header */
        p_bg += (H5_SIZEOF_UINT32_T + H5R_ENCODE_HEADER_SIZE);
        HDassert(p_buf_size_left > (H5_SIZEOF_UINT32_T + H5R_ENCODE_HEADER_SIZE));
        p_buf_size_left -= (H5_SIZEOF_UINT32_T + H5R_ENCODE_HEADER_SIZE);

        /* Remove blob for old data */
        if(H5VL_blob_specific(dst_file, (void *)p_bg, H5VL_BLOB_DELETE) < 0)
            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREMOVE, FAIL, "unable to delete blob")
    } /* end if */

    /* Copy header manually so that it does not get encoded into the blob */
    HDmemcpy(q, p, H5R_ENCODE_HEADER_SIZE);
    p += H5R_ENCODE_HEADER_SIZE;
    q += H5R_ENCODE_HEADER_SIZE;
    src_size -= H5R_ENCODE_HEADER_SIZE;
    buf_size_left -= H5_SIZEOF_UINT32_T;

    /* Set the size */
    UINT32ENCODE(q, src_size);
    HDassert(buf_size_left > H5_SIZEOF_UINT32_T);
    buf_size_left -= H5_SIZEOF_UINT32_T;

    /* Store blob */
    if(H5VL_blob_put(dst_file, p, src_size, q, NULL) < 0)
        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "unable to put blob")

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_disk_write() */


/*-------------------------------------------------------------------------
 * Function:    H5T__ref_obj_disk_isnull
 *
 * Purpose: Check if it's a NULL / uninitialized reference.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t H5T__ref_obj_disk_isnull(const H5VL_object_t *src_file,
    const void *src_buf, hbool_t *isnull)
{
    H5F_t *src_f;
    const uint8_t *p = (const uint8_t *)src_buf;
    haddr_t addr;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    /* Check parameters */
    HDassert(src_file);
    HDassert(src_buf);
    HDassert(isnull);

    /* We should assert here that the terminal connector is H5VL_NATIVE once
     * there is a facility to do so -NAF 2019/10/30 */

    /* Retrieve file from VOL object */
    if(NULL == (src_f = (H5F_t *)H5VL_object_data(src_file)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid VOL object")

    /* Get the object address */
    H5F_addr_decode(src_f, &p, &addr);

    /* Check if heap address is 'nil' */
    *isnull = (addr == 0) ? TRUE : FALSE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_obj_disk_isnull() */


/*-------------------------------------------------------------------------
 * Function:    H5T__ref_obj_disk_getsize
 *
 * Purpose: Retrieves the length of a disk based reference.
 *
 * Return:  Non-negative value (cannot fail)
 *
 *-------------------------------------------------------------------------
 */
static size_t
H5T__ref_obj_disk_getsize(H5VL_object_t *src_file, const void H5_ATTR_UNUSED *src_buf,
    size_t H5_ATTR_UNUSED src_size, H5VL_object_t H5_ATTR_UNUSED *dst_file,
    hbool_t H5_ATTR_UNUSED *dst_copy)
{
    H5F_t *src_f;
    size_t ret_value = 0;

    FUNC_ENTER_STATIC

    HDassert(src_file);
    HDassert(src_buf);

    /* We should assert here that the terminal connector is H5VL_NATIVE once
     * there is a facility to do so -NAF 2019/10/30 */

    /* Retrieve file from VOL object */
    if(NULL == (src_f = (H5F_t *)H5VL_object_data(src_file)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, 0, "invalid VOL object")

    HDassert(src_size == H5T_REF_OBJ_DISK_SIZE(src_f));

    ret_value = H5T_REF_OBJ_DISK_SIZE(src_f);

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_obj_disk_getsize() */


/*-------------------------------------------------------------------------
 * Function:    H5T__ref_obj_disk_read
 *
 * Purpose: Reads the disk based reference into a buffer
 *
 * Return:  Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_obj_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size,
    H5VL_object_t H5_ATTR_UNUSED *dst_file, void *dst_buf, size_t H5_ATTR_UNUSED dst_size)
{
    H5F_t *src_f;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    HDassert(src_file);
    HDassert(src_buf);
    HDassert(dst_buf);

    /* We should assert here that the terminal connector is H5VL_NATIVE once
     * there is a facility to do so -NAF 2019/10/30 */

    /* Retrieve file from VOL object */
    if(NULL == (src_f = (H5F_t *)H5VL_object_data(src_file)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid VOL object")

    HDassert(src_size == H5T_REF_OBJ_DISK_SIZE(src_f));
    HDassert(dst_size == H5F_SIZEOF_ADDR(src_f));

    /* Get object address */
    if(H5R__decode_token_obj_compat((const unsigned char *)src_buf, &src_size,
        (H5VL_token_t *)dst_buf, H5F_SIZEOF_ADDR(src_f)) < 0)
        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, FAIL, "unable to get object address")

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_obj_disk_read() */


/*-------------------------------------------------------------------------
 * Function:    H5T__ref_dsetreg_disk_isnull
 *
 * Purpose: Check if it's a NULL / uninitialized reference.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_dsetreg_disk_isnull(const H5VL_object_t *src_file, const void *src_buf,
    hbool_t *isnull)
{
    H5F_t *src_f;
    const uint8_t *p = (const uint8_t *)src_buf;
    haddr_t addr;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    /* Check parameters */
    HDassert(src_file);
    HDassert(src_buf);
    HDassert(isnull);

    /* We should assert here that the terminal connector is H5VL_NATIVE once
     * there is a facility to do so -NAF 2019/10/30 */

    /* Retrieve file from VOL object */
    if(NULL == (src_f = (H5F_t *)H5VL_object_data(src_file)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid VOL object")

    /* Get the heap address */
    H5F_addr_decode(src_f, &p, &addr);

    /* Check if heap address is 'nil' */
    *isnull = (addr == 0) ? TRUE : FALSE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_dsetreg_disk_isnull() */


/*-------------------------------------------------------------------------
 * Function:    H5T__ref_dsetreg_disk_getsize
 *
 * Purpose: Retrieves the length of a disk based reference.
 *
 * Return:  Non-negative value (cannot fail)
 *
 *-------------------------------------------------------------------------
 */
static size_t
H5T__ref_dsetreg_disk_getsize(H5VL_object_t H5_ATTR_UNUSED *src_file,
    const void H5_ATTR_UNUSED *src_buf, size_t H5_ATTR_UNUSED src_size,
    H5VL_object_t H5_ATTR_UNUSED *dst_file, hbool_t H5_ATTR_UNUSED *dst_copy)
{
    size_t ret_value = sizeof(struct H5Tref_dsetreg);

#ifndef NDEBUG
    FUNC_ENTER_STATIC
#else
    FUNC_ENTER_STATIC_NOERR
#endif

    HDassert(src_buf);

#ifndef NDEBUG
    {
        H5F_t *src_f;

        /* We should assert here that the terminal connector is H5VL_NATIVE once
         * there is a facility to do so -NAF 2019/10/30 */

        /* Retrieve file from VOL object */
        if(NULL == (src_f = (H5F_t *)H5VL_object_data(src_file)))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, 0, "invalid VOL object")

        HDassert(src_size == H5T_REF_DSETREG_DISK_SIZE(src_f));
    } /* end block */
#endif /* NDEBUG */

#ifndef NDEBUG
done:
#endif
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_dsetreg_disk_getsize() */


/*-------------------------------------------------------------------------
 * Function:    H5T__ref_dsetreg_disk_read
 *
 * Purpose: Reads the disk based reference into a buffer
 *
 * Return:  Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T__ref_dsetreg_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size,
    H5VL_object_t H5_ATTR_UNUSED *dst_file, void *dst_buf, size_t H5_ATTR_UNUSED dst_size)
{
    H5F_t *src_f;
    struct H5Tref_dsetreg *dst_reg = (struct H5Tref_dsetreg *)dst_buf;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    HDassert(src_file);
    HDassert(src_buf);
    HDassert(dst_buf);
    HDassert(dst_size == sizeof(struct H5Tref_dsetreg));

    /* We should assert here that the terminal connector is H5VL_NATIVE once
     * there is a facility to do so -NAF 2019/10/30 */

    /* Retrieve file from VOL object */
    if(NULL == (src_f = (H5F_t *)H5VL_object_data(src_file)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid VOL object")

    HDassert(src_size == H5T_REF_DSETREG_DISK_SIZE(src_f));

    /* Retrieve object address and space */
    if(H5R__decode_token_region_compat(src_f, (const unsigned char *)src_buf,
        &src_size, &dst_reg->token, H5F_SIZEOF_ADDR(src_f), &dst_reg->space) < 0)
        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, FAIL, "unable to get object address")

done:
    FUNC_LEAVE_NOAPI(ret_value)
}   /* end H5T__ref_dsetreg_disk_read() */


/*-------------------------------------------------------------------------
 * Function:    H5T_ref_reclaim
 *
 * Purpose: Internal routine to free reference datatypes
 *
 * Return:  Non-negative on success / Negative on failure
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5T_ref_reclaim(void *elem, const H5T_t *dt)
{
    herr_t ret_value = SUCCEED;     /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Sanity checks */
    HDassert(elem);
    HDassert(dt && (dt->shared->type == H5T_REFERENCE));

    if(dt->shared->u.atomic.u.r.opaque
        && (H5R__destroy((H5R_ref_priv_t *)elem) < 0))
        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTFREE, FAIL, "cannot free reference")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5T_ref_reclaim() */