Add new H5R API that abstracts object, region and attribute reference types

Also support references to external files

Add new H5T_REF type and type conversion routines

Support conversion from H5T_REF_OBJ/DSET_REG to H5T_REF

Add H5Treclaim() API to reclaim memory of vlen/reference types

Deprecate H5Dvlen_reclaim()

Fix H5T_vlen_reclaim() and H5T_reclaim() to use private callback

Add H5T_ref_reclaim()

Move previous H5R APIs to H5Rdeprec.c

Clean up H5Ocopy

Separate H5O_copy_expand_ref() to H5Ocopy_ref()

Add support for copying new reference types

Clean up deprecated routines to go through VOL and same code path

Fix return codes in existing trefer.c test

Rename trefer.c to trefer_deprec.c

trefer.c is for new references

Add performance test for trefer

Add additional obj_copy_ref test

Make use of tokens and blobs to store references

Skip blob encoding for object references

Start adding new reference examples

1 files changed, 735 insertions, 238 deletions

diff --git a/src/H5R.c b/src/H5R.c
index 7d3686e..11b75ca 100644
--- a/src/H5R.c
+++ b/src/H5R.c
@@ -11,22 +11,24 @@
  * help@hdfgroup.org.                                                        *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
+/*
+ * Purpose:     Reference routines.
+ */
+
 /****************/
 /* Module Setup */
 /****************/
 
 #include "H5Rmodule.h"          /* This source code file is part of the H5R module */
 
-
 /***********/
 /* Headers */
 /***********/
 #include "H5private.h"          /* Generic Functions                        */
-#include "H5ACprivate.h"        /* Metadata cache                           */
 #include "H5CXprivate.h"        /* API Contexts                             */
 #include "H5Eprivate.h"         /* Error handling                           */
-#include "H5Gprivate.h"         /* Groups                                   */
 #include "H5Iprivate.h"         /* IDs                                      */
+#include "H5MMprivate.h"        /* Memory management                        */
 #include "H5Rpkg.h"             /* References                               */
 #include "H5Sprivate.h"         /* Dataspaces                               */
 
@@ -61,330 +63,825 @@
 /*******************/
 
 
-/*--------------------------------------------------------------------------
- NAME
-    H5Rcreate
- PURPOSE
-    Creates a particular kind of reference for the user
- USAGE
-    herr_t H5Rcreate(ref, loc_id, name, ref_type, space_id)
-        void *ref;          OUT: Reference created
-        hid_t loc_id;       IN: Location ID used to locate object pointed to
-        const char *name;   IN: Name of object at location LOC_ID of object
-                                    pointed to
-        H5R_type_t ref_type;    IN: Type of reference to create
-        hid_t space_id;     IN: Dataspace ID with selection, used for Dataset
-                                    Region references.
-
- RETURNS
-    Non-negative on success/Negative on failure
- DESCRIPTION
-    Creates a particular type of reference specified with REF_TYPE, in the
-    space pointed to by REF.  The LOC_ID and NAME are used to locate the object
-    pointed to and the SPACE_ID is used to choose the region pointed to (for
-    Dataset Region references).
- GLOBAL VARIABLES
- COMMENTS, BUGS, ASSUMPTIONS
- EXAMPLES
- REVISION LOG
---------------------------------------------------------------------------*/
+/*-------------------------------------------------------------------------
+ * Function:    H5Rcreate_object
+ *
+ * Purpose: Creates an object reference. The LOC_ID and NAME are used to locate
+ * the object pointed to.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
 herr_t
-H5Rcreate(void *ref, hid_t loc_id, const char *name, H5R_type_t ref_type, hid_t space_id)
+H5Rcreate_object(hid_t loc_id, const char *name, H5R_ref_t *ref_ptr)
 {
-    H5VL_object_t      *vol_obj = NULL;         /* Object token of loc_id */
-    H5VL_loc_params_t   loc_params;
-    herr_t              ret_value;              /* Return value */
+    H5VL_object_t *vol_obj = NULL;  /* Object token of loc_id */
+    H5I_type_t obj_type;            /* Object type of loc_id */
+    hid_t file_id = H5I_INVALID_HID;/* File ID */
+    H5VL_object_t *vol_obj_file = NULL; /* Object token of file_id */
+    H5VL_loc_params_t loc_params;   /* Location parameters */
+    H5VL_token_t obj_token = {0};   /* Object token */
+    H5VL_file_cont_info_t cont_info = {H5VL_CONTAINER_INFO_VERSION, 0, 0, 0};
+    herr_t ret_value = SUCCEED;     /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE5("e", "*xi*sRti", ref, loc_id, name, ref_type, space_id);
+    H5TRACE3("e", "i*s*Rr", loc_id, name, ref_ptr);
 
     /* Check args */
-    if (ref == NULL)
+    if(ref_ptr == NULL)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference pointer")
     if(!name || !*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name given")
-    if(ref_type <= H5R_BADTYPE || ref_type >= H5R_MAXTYPE)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference type")
-    if(ref_type != H5R_OBJECT && ref_type != H5R_DATASET_REGION)
-        HGOTO_ERROR(H5E_ARGS, H5E_UNSUPPORTED, FAIL, "reference type not supported")
-    if(space_id == (-1) && ref_type == H5R_DATASET_REGION)
+
+    /* Get the VOL object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+    /* Get object type */
+    if((obj_type = H5I_get_type(loc_id)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+    /* Get the file for the object */
+    if((file_id = H5F_get_file_id(loc_id, obj_type, FALSE)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
+
+    /* Retrieve VOL file object */
+    if(NULL == (vol_obj_file = H5VL_vol_object(file_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+    /* Get container info */
+    if(H5VL_file_get(vol_obj_file, H5VL_FILE_GET_CONT_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &cont_info) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to get container info")
+
+    /* Set location parameters */
+    loc_params.type = H5VL_OBJECT_BY_NAME;
+    loc_params.loc_data.loc_by_name.name = name;
+    loc_params.obj_type = obj_type;
+
+    /* Get the object token */
+    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, obj_token) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to retrieve object token")
+
+    /* Create the reference (do not pass filename, since file_id is attached) */
+    HDmemset(ref_ptr, 0, H5R_REF_BUF_SIZE);
+    if(H5R__create_object((const H5VL_token_t *)&obj_token, cont_info.token_size, (H5R_ref_priv_t *)ref_ptr) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCREATE, FAIL, "unable to create object reference")
+
+    /* Attach loc_id to reference and hold reference to it */
+    if(H5R__set_loc_id((H5R_ref_priv_t *)ref_ptr, 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 file")
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Rcreate_object() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Rcreate_region
+ *
+ * Purpose: Creates a region reference. The LOC_ID and NAME are used to locate
+ * the object pointed to and the SPACE_ID is used to choose the region pointed
+ * to.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Rcreate_region(hid_t loc_id, const char *name, hid_t space_id,
+    H5R_ref_t *ref_ptr)
+{
+    H5VL_object_t *vol_obj = NULL;  /* Object token of loc_id */
+    H5I_type_t obj_type;            /* Object type of loc_id */
+    hid_t file_id = H5I_INVALID_HID;/* File ID */
+    H5VL_object_t *vol_obj_file = NULL; /* Object token of file_id */
+    H5VL_loc_params_t loc_params;   /* Location parameters */
+    H5VL_token_t obj_token = {0};   /* Object token */
+    H5VL_file_cont_info_t cont_info = {H5VL_CONTAINER_INFO_VERSION, 0, 0, 0};
+    struct H5S_t *space = NULL;     /* Pointer to dataspace containing region */
+    herr_t ret_value = SUCCEED;     /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE4("e", "i*si*Rr", loc_id, name, space_id, ref_ptr);
+
+    /* Check args */
+    if(ref_ptr == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference pointer")
+    if(!name || !*name)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name given")
+    if((space_id == H5I_BADID) || (space_id == H5S_ALL))
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "reference region dataspace id must be valid")
+    if(NULL == (space = (struct H5S_t *)H5I_object_verify(space_id, H5I_DATASPACE)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a dataspace")
+
+    /* Get the VOL object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+    /* Get object type */
+    if((obj_type = H5I_get_type(loc_id)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+    /* Get the file for the object */
+    if((file_id = H5F_get_file_id(loc_id, obj_type, FALSE)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
+
+    /* Retrieve VOL file object */
+    if(NULL == (vol_obj_file = H5VL_vol_object(file_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+    /* Get container info */
+    if(H5VL_file_get(vol_obj_file, H5VL_FILE_GET_CONT_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &cont_info) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to get container info")
+
+    /* Set location parameters */
+    loc_params.type = H5VL_OBJECT_BY_NAME;
+    loc_params.loc_data.loc_by_name.name = name;
+    loc_params.obj_type = obj_type;
+
+    /* Get the object token */
+    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, obj_token) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to retrieve object token")
+
+    /* Create the reference (do not pass filename, since file_id is attached) */
+    HDmemset(ref_ptr, 0, H5R_REF_BUF_SIZE);
+    if(H5R__create_region((const H5VL_token_t *)&obj_token, cont_info.token_size, space, (H5R_ref_priv_t *)ref_ptr) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCREATE, FAIL, "unable to create region reference")
+
+    /* Attach loc_id to reference and hold reference to it */
+    if(H5R__set_loc_id((H5R_ref_priv_t *)ref_ptr, 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, H5I_INVALID_HID, "unable to decrement refcount on file")
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Rcreate_region() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Rcreate_attr
+ *
+ * Purpose: Creates an attribute reference. The LOC_ID, NAME and ATTR_NAME are
+ * used to locate the attribute pointed to.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Rcreate_attr(hid_t loc_id, const char *name, const char *attr_name,
+    H5R_ref_t *ref_ptr)
+{
+    H5VL_object_t *vol_obj = NULL;  /* Object token of loc_id */
+    H5I_type_t obj_type;            /* Object type of loc_id */
+    hid_t file_id = H5I_INVALID_HID;/* File ID */
+    H5VL_object_t *vol_obj_file = NULL; /* Object token of file_id */
+    H5VL_loc_params_t loc_params;   /* Location parameters */
+    H5VL_token_t obj_token = {0};   /* Object token */
+    H5VL_file_cont_info_t cont_info = {H5VL_CONTAINER_INFO_VERSION, 0, 0, 0};
+    herr_t ret_value = SUCCEED;     /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE4("e", "i*s*s*Rr", loc_id, name, attr_name, ref_ptr);
+
+    /* Check args */
+    if(ref_ptr == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference pointer")
+    if(!name || !*name)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name given")
+    if(!attr_name || !*attr_name)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no attribute name given")
+
+    /* Get the VOL object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+    /* Get object type */
+    if((obj_type = H5I_get_type(loc_id)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
-    /* Set up collective metadata if appropriate */
-    if(H5CX_set_loc(loc_id) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTSET, FAIL, "can't set access property list info")
+    /* Get the file for the object */
+    if((file_id = H5F_get_file_id(loc_id, obj_type, FALSE)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
+
+    /* Retrieve VOL file object */
+    if(NULL == (vol_obj_file = H5VL_vol_object(file_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+    /* Get container info */
+    if(H5VL_file_get(vol_obj_file, H5VL_FILE_GET_CONT_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &cont_info) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to get container info")
 
     /* Set location parameters */
-    loc_params.type         = H5VL_OBJECT_BY_SELF;
-    loc_params.obj_type     = H5I_get_type(loc_id);
+    loc_params.type = H5VL_OBJECT_BY_NAME;
+    loc_params.loc_data.loc_by_name.name = name;
+    loc_params.obj_type = obj_type;
+
+    /* Get the object token */
+    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, obj_token) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to retrieve object token")
+
+    /* Create the reference (do not pass filename, since file_id is attached) */
+    HDmemset(ref_ptr, 0, H5R_REF_BUF_SIZE);
+    if(H5R__create_attr((const H5VL_token_t *)&obj_token, cont_info.token_size, attr_name, (H5R_ref_priv_t *)ref_ptr) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCREATE, FAIL, "unable to create attribute reference")
+
+    /* Attach loc_id to reference and hold reference to it */
+    if(H5R__set_loc_id((H5R_ref_priv_t *)ref_ptr, 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, H5I_INVALID_HID, "unable to decrement refcount on file")
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Rcreate_attr() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Rdestroy
+ *
+ * Purpose: Destroy reference and free resources allocated during H5Rcreate.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Rdestroy(H5R_ref_t *ref_ptr)
+{
+    herr_t ret_value = SUCCEED;                 /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE1("e", "*Rr", ref_ptr);
+
+    /* Check args */
+    if(NULL == ref_ptr)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid reference pointer")
+
+    /* Destroy reference */
+    if(H5R__destroy((H5R_ref_priv_t *)ref_ptr) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTFREE, FAIL, "unable to destroy reference")
+
+    /* Memset back to 0 for safety */
+    HDmemset(ref_ptr, 0, H5R_REF_BUF_SIZE);
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Rdestroy() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Rget_type
+ *
+ * Purpose: Given a reference to some object, return the type of that reference.
+ *
+ * Return:  Reference type/H5R_BADTYPE on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+H5R_type_t
+H5Rget_type(const H5R_ref_t *ref_ptr)
+{
+    H5R_type_t ret_value;   /* Return value */
+
+    FUNC_ENTER_API(H5R_BADTYPE)
+    H5TRACE1("Rt", "*Rr", ref_ptr);
+
+    /* Check args */
+    if(NULL == ref_ptr)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5R_BADTYPE, "invalid reference pointer")
+
+    /* Get reference type */
+    ret_value = H5R__get_type((const H5R_ref_priv_t *)ref_ptr);
+    if((ret_value <= H5R_BADTYPE) || (ret_value >= H5R_MAXTYPE))
+        HGOTO_ERROR(H5E_REFERENCE, H5E_BADVALUE, H5R_BADTYPE, "invalid reference type")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Rget_type() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Requal
+ *
+ * Purpose: Compare two references
+ *
+ * Return:  TRUE if equal, FALSE if unequal, FAIL if error
+ *
+ *-------------------------------------------------------------------------
+ */
+htri_t
+H5Requal(const H5R_ref_t *ref1_ptr, const H5R_ref_t *ref2_ptr)
+{
+    htri_t ret_value;   /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE2("t", "*Rr*Rr", ref1_ptr, ref2_ptr);
+
+    /* Check args */
+    if(!ref1_ptr || !ref2_ptr)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference pointer")
+
+    /* Compare references */
+    if((ret_value = H5R__equal((const H5R_ref_priv_t *)ref2_ptr, (const H5R_ref_priv_t *)ref2_ptr)) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCOMPARE, FAIL, "cannot compare references")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Requal() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Rcopy
+ *
+ * Purpose: Copy a reference
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Rcopy(const H5R_ref_t *src_ref_ptr, H5R_ref_t *dst_ref_ptr)
+{
+    herr_t ret_value = SUCCEED; /* Return value */
 
-    /* Get the file object */
-    if (NULL == (vol_obj = (H5VL_object_t *)H5I_object(loc_id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
+    FUNC_ENTER_API(FAIL)
+    H5TRACE2("e", "*Rr*Rr", src_ref_ptr, dst_ref_ptr);
 
-    /* Set up collective metadata if appropriate */
-    if(H5CX_set_loc(loc_id) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTSET, FAIL, "can't set access property list info")
+    /* Check args */
+    if(NULL == src_ref_ptr || NULL == dst_ref_ptr)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid reference pointer")
 
-    /* Create reference */
-    if((ret_value = H5VL_object_specific(vol_obj, &loc_params, H5VL_REF_CREATE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, ref, name, (int)ref_type, space_id)) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCREATE, FAIL, "unable to create reference")
+    /* Copy reference */
+    if(H5R__copy((const H5R_ref_priv_t *)src_ref_ptr, (H5R_ref_priv_t *)dst_ref_ptr) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCOPY, FAIL, "cannot copy reference")
 
 done:
     FUNC_LEAVE_API(ret_value)
-}   /* end H5Rcreate() */
+} /* end H5Rcopy() */
 
 
-/*--------------------------------------------------------------------------
- NAME
-    H5Rdereference2
- PURPOSE
-    Opens the HDF5 object referenced.
- USAGE
-    hid_t H5Rdereference2(ref)
-        hid_t id;       IN: Dataset reference object is in or location ID of
-                            object that the dataset is located within.
-        hid_t oapl_id;  IN: Property list of the object being referenced.
-        H5R_type_t ref_type;    IN: Type of reference to create
-        void *ref;      IN: Reference to open.
-
- RETURNS
-    Valid ID on success, H5I_INVALID_HID on failure
- DESCRIPTION
-    Given a reference to some object, open that object and return an ID for
-    that object.
- GLOBAL VARIABLES
- COMMENTS, BUGS, ASSUMPTIONS
- EXAMPLES
- REVISION LOG
-    Raymond Lu
-    13 July 2011
-    I added the OAPL_ID parameter for the object being referenced.  It only
-    supports dataset access property list currently.
---------------------------------------------------------------------------*/
+/*-------------------------------------------------------------------------
+ * Function:    H5Ropen_object
+ *
+ * Purpose: Given a reference to some object, open that object and return an
+ * ID for that object.
+ *
+ * Return:  Valid ID on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
 hid_t
-H5Rdereference2(hid_t obj_id, hid_t oapl_id, H5R_type_t ref_type, const void *_ref)
+H5Ropen_object(const H5R_ref_t *ref_ptr, hid_t rapl_id, hid_t oapl_id)
 {
-    H5VL_object_t *vol_obj = NULL;        /* object token of loc_id */
-    H5I_type_t opened_type;
-    void *opened_obj = NULL;
-    H5VL_loc_params_t loc_params;
-    hid_t ret_value = H5I_INVALID_HID;	/* Return value */
+    hid_t loc_id;                       /* Reference location ID */
+    H5VL_object_t *vol_obj = NULL;      /* Object token of loc_id */
+    H5VL_loc_params_t loc_params;       /* Location parameters */
+    H5VL_token_t obj_token = {0};       /* Object token */
+    H5I_type_t opened_type;             /* Opened object type */
+    void *opened_obj = NULL;            /* Opened object */
+    hid_t ret_value = H5I_INVALID_HID;  /* Return value */
 
     FUNC_ENTER_API(H5I_INVALID_HID)
-    H5TRACE4("i", "iiRt*x", obj_id, oapl_id, ref_type, _ref);
+    H5TRACE3("i", "*Rrii", ref_ptr, rapl_id, oapl_id);
 
     /* Check args */
+    if(ref_ptr == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid reference pointer")
+    if(H5R__get_type((const H5R_ref_priv_t *)ref_ptr) <= H5R_BADTYPE
+        || H5R__get_type((const H5R_ref_priv_t *)ref_ptr) >= H5R_MAXTYPE)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid reference type")
+    if(rapl_id < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a property list")
     if(oapl_id < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a property list")
-    if(ref_type <= H5R_BADTYPE || ref_type >= H5R_MAXTYPE)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid reference type")
-    if(_ref == NULL)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid reference pointer")
+
+    /* Retrieve loc_id from reference */
+    if(H5I_INVALID_HID == (loc_id = H5R__get_loc_id((const H5R_ref_priv_t *)ref_ptr))) {
+        /* Attempt to re-open file and pass rapl_id as a fapl_id */
+        if((loc_id = H5R__reopen_file((H5R_ref_priv_t *)ref_ptr, rapl_id)) < 0)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENFILE, H5I_INVALID_HID, "cannot re-open referenced file")
+    }
+
+    /* Get object token */
+    if(H5R__get_obj_token((const H5R_ref_priv_t *)ref_ptr, &obj_token, NULL) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, H5I_INVALID_HID, "unable to get object token")
 
     /* Verify access property list and set up collective metadata if appropriate */
-    if(H5CX_set_apl(&oapl_id, H5P_CLS_DACC, obj_id, FALSE) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTSET, FAIL, "can't set access property list info")
+    if(H5CX_set_apl(&oapl_id, H5P_CLS_DACC, loc_id, FALSE) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTSET, H5I_INVALID_HID, "can't set access property list info")
 
     /* Get the VOL object */
-    if(NULL == (vol_obj = H5VL_vol_object(obj_id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid file identifier")
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
 
     /* Set location parameters */
-    loc_params.type                             = H5VL_OBJECT_BY_REF;
-    loc_params.loc_data.loc_by_ref.ref_type     = ref_type;
-    loc_params.loc_data.loc_by_ref._ref         = _ref;
-    loc_params.loc_data.loc_by_ref.lapl_id      = oapl_id;
-    loc_params.obj_type                         = H5I_get_type(obj_id);
+    loc_params.type = H5VL_OBJECT_BY_TOKEN;
+    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.obj_type = H5I_get_type(loc_id);
 
-    /* Dereference */
+    /* Open object by token */
     if(NULL == (opened_obj = H5VL_object_open(vol_obj, &loc_params, &opened_type, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to dereference object")
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to open object by token")
 
+    /* Register object */
     if((ret_value = H5VL_register(opened_type, opened_obj, vol_obj->connector, TRUE)) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to register object handle")
 
 done:
     FUNC_LEAVE_API(ret_value)
-}   /* end H5Rdereference2() */
+} /* end H5Ropen_object() */
 
 
-/*--------------------------------------------------------------------------
- NAME
-    H5Rget_region
- PURPOSE
-    Retrieves a dataspace with the region pointed to selected.
- USAGE
-    hid_t H5Rget_region(id, ref_type, ref)
-        hid_t id;       IN: Dataset reference object is in or location ID of
-                            object that the dataset is located within.
-        H5R_type_t ref_type;    IN: Type of reference to get region of
-        void *ref;        IN: Reference to open.
-
- RETURNS
-    Valid ID on success, H5I_INVALID_HID on failure
- DESCRIPTION
-    Given a reference to some object, creates a copy of the dataset pointed
-    to's dataspace and defines a selection in the copy which is the region
-    pointed to.
- GLOBAL VARIABLES
- COMMENTS, BUGS, ASSUMPTIONS
- EXAMPLES
- REVISION LOG
---------------------------------------------------------------------------*/
+/*-------------------------------------------------------------------------
+ * Function:    H5Ropen_region
+ *
+ * Purpose: Given a reference to some object, creates a copy of the dataset
+ * pointed to's dataspace and defines a selection in the copy which is the
+ * region pointed to.
+ *
+ * Return:  Valid ID on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
 hid_t
-H5Rget_region(hid_t id, H5R_type_t ref_type, const void *ref)
+H5Ropen_region(const H5R_ref_t *ref_ptr, hid_t rapl_id, hid_t oapl_id)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    hid_t ret_value = H5I_INVALID_HID;	/* Return value */
+    hid_t loc_id;                           /* Reference location ID */
+    H5VL_object_t *vol_obj = NULL;          /* Object token of loc_id */
+    H5VL_loc_params_t loc_params;           /* Location parameters */
+    H5VL_token_t obj_token = {0};           /* Object token */
+    H5I_type_t opened_type;                 /* Opened object type */
+    void *opened_obj = NULL;                /* Opened object */
+    hid_t opened_obj_id = H5I_INVALID_HID;  /* Opened object ID */
+    H5S_t *space = NULL;                    /* Dataspace pointer (copy) */
+    hid_t space_id = H5I_INVALID_HID;       /* Dataspace ID */
+    hid_t ret_value = H5I_INVALID_HID;      /* Return value */
 
     FUNC_ENTER_API(H5I_INVALID_HID)
-    H5TRACE3("i", "iRt*x", id, ref_type, ref);
+    H5TRACE3("i", "*Rrii", ref_ptr, rapl_id, oapl_id);
 
     /* Check args */
-    if(ref_type != H5R_DATASET_REGION)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid reference type")
-    if(ref == NULL)
+    if(ref_ptr == NULL)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid reference pointer")
+    if((H5R__get_type((const H5R_ref_priv_t *)ref_ptr) != H5R_DATASET_REGION1)
+        && (H5R__get_type((const H5R_ref_priv_t *)ref_ptr) != H5R_DATASET_REGION2))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid reference type")
+    if(rapl_id < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a property list")
+    if(oapl_id < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a property list")
+
+    /* Retrieve loc_id from reference */
+    if(H5I_INVALID_HID == (loc_id = H5R__get_loc_id((const H5R_ref_priv_t *)ref_ptr))) {
+        /* Attempt to re-open file and pass rapl_id as a fapl_id */
+        if((loc_id = H5R__reopen_file((H5R_ref_priv_t *)ref_ptr, rapl_id)) < 0)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENFILE, H5I_INVALID_HID, "cannot re-open referenced file")
+    }
+
+    /* Get object token */
+    if(H5R__get_obj_token((const H5R_ref_priv_t *)ref_ptr, &obj_token, NULL) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, H5I_INVALID_HID, "unable to get object token")
+
+    /* Get the VOL object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
 
     /* Set location parameters */
-    loc_params.type         = H5VL_OBJECT_BY_SELF;
-    loc_params.obj_type     = H5I_get_type(id);
+    loc_params.type = H5VL_OBJECT_BY_TOKEN;
+    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.obj_type = H5I_get_type(loc_id);
 
-    /* get the file object */
-    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object(id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid file identifier")
+    /* Open object by token */
+    if(NULL == (opened_obj = H5VL_object_open(vol_obj, &loc_params, &opened_type, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to open object by token")
+
+    /* Register object */
+    if((opened_obj_id = H5VL_register(opened_type, opened_obj, vol_obj->connector, FALSE)) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to register object handle")
+
+    /* Get VOL object object */
+    if(NULL == (opened_obj = H5VL_vol_object(opened_obj_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
+
+    /* Get dataspace from object */
+    if(H5VL_dataset_get(opened_obj, H5VL_DATASET_GET_SPACE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &space_id) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, H5I_INVALID_HID, "unable to get dataspace from dataset")
+    if(NULL == (space = (struct H5S_t *)H5I_object_verify(space_id, H5I_DATASPACE)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a dataspace")
 
     /* Get the dataspace with the correct region selected */
-    if(H5VL_object_get(vol_obj, &loc_params, H5VL_REF_GET_REGION, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &ret_value, (int)ref_type, ref) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, H5I_INVALID_HID, "unable to retrieve dataspace")
+    if(H5R__get_region((const H5R_ref_priv_t *)ref_ptr, space) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, H5I_INVALID_HID, "unable to get selection on dataspace")
+
+    /* Simply return space_id */
+    ret_value = space_id;
+
+done:
+    if((opened_obj_id != H5I_INVALID_HID) && (H5I_dec_ref(opened_obj_id) < 0))
+        HDONE_ERROR(H5E_REFERENCE, H5E_CLOSEERROR, H5I_INVALID_HID, "can't close object")
+    if(H5I_INVALID_HID == ret_value) /* Cleanup on failure */
+        if((space_id != H5I_INVALID_HID) && (H5I_dec_ref(space_id) < 0))
+        HDONE_ERROR(H5E_REFERENCE, H5E_CLOSEERROR, H5I_INVALID_HID, "can't close dataspace")
+
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Ropen_region() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Ropen_attr
+ *
+ * Purpose: Given a reference to some attribute, open that attribute and
+ * return an ID for that attribute.
+ *
+ * Return:  Valid ID on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5Ropen_attr(const H5R_ref_t *ref_ptr, hid_t rapl_id, hid_t aapl_id)
+{
+    hid_t loc_id;                           /* Reference location ID */
+    H5VL_object_t *vol_obj = NULL;          /* Object token of loc_id */
+    H5VL_loc_params_t loc_params;           /* Location parameters */
+    H5VL_token_t obj_token = {0};           /* Object token */
+    H5I_type_t opened_type;                 /* Opened object type */
+    void *opened_obj = NULL;                /* Opened object */
+    hid_t opened_obj_id = H5I_INVALID_HID;  /* Opened object ID */
+    void *opened_attr = NULL;               /* Opened attribute */
+    hid_t ret_value = H5I_INVALID_HID;      /* Return value */
+
+    FUNC_ENTER_API(H5I_INVALID_HID)
+    H5TRACE3("i", "*Rrii", ref_ptr, rapl_id, aapl_id);
+
+    /* Check args */
+    if(ref_ptr == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid reference pointer")
+    if(H5R__get_type((const H5R_ref_priv_t *)ref_ptr) != H5R_ATTR)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid reference type")
+    if(rapl_id < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a property list")
+    if(aapl_id < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a property list")
+
+    /* Retrieve loc_id from reference */
+    if(H5I_INVALID_HID == (loc_id = H5R__get_loc_id((const H5R_ref_priv_t *)ref_ptr))) {
+        /* Attempt to re-open file and pass rapl_id as a fapl_id */
+        if((loc_id = H5R__reopen_file((H5R_ref_priv_t *)ref_ptr, rapl_id)) < 0)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENFILE, H5I_INVALID_HID, "cannot re-open referenced file")
+    }
+
+    /* Get object token */
+    if(H5R__get_obj_token((const H5R_ref_priv_t *)ref_ptr, &obj_token, NULL) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, H5I_INVALID_HID, "unable to get object token")
+
+    /* Get the VOL object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
+
+    /* Set location parameters */
+    loc_params.type = H5VL_OBJECT_BY_TOKEN;
+    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.obj_type = H5I_get_type(loc_id);
+
+    /* Open object by token */
+    if(NULL == (opened_obj = H5VL_object_open(vol_obj, &loc_params, &opened_type, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to open object by token")
+
+    /* Register object */
+    if((opened_obj_id = H5VL_register(opened_type, opened_obj, vol_obj->connector, FALSE)) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to register object handle")
+
+    /* Verify access property list and set up collective metadata if appropriate */
+    if(H5CX_set_apl(&aapl_id, H5P_CLS_AACC, loc_id, FALSE) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, H5I_INVALID_HID, "can't set access property list info")
+
+    /* Set location parameters */
+    loc_params.type = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = opened_type;
+
+    /* Get VOL object object */
+    if(NULL == (opened_obj = H5VL_vol_object(opened_obj_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
+
+    /* Open the attribute */
+    if(NULL == (opened_attr = H5VL_attr_open(opened_obj, &loc_params, H5R_REF_ATTRNAME((const H5R_ref_priv_t *)ref_ptr), aapl_id, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to open attribute: '%s'", H5R_REF_ATTRNAME((const H5R_ref_priv_t *)ref_ptr))
+
+    /* Register the attribute and get an ID for it */
+    if((ret_value = H5VL_register(H5I_ATTR, opened_attr, vol_obj->connector, TRUE)) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize attribute handle")
 
 done:
+    if((opened_obj_id != H5I_INVALID_HID) && (H5I_dec_ref(opened_obj_id) < 0))
+        HDONE_ERROR(H5E_REFERENCE, H5E_CLOSEERROR, H5I_INVALID_HID, "can't close object")
+    if(H5I_INVALID_HID == ret_value) /* Cleanup on failure */
+        if(opened_attr && H5VL_attr_close(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
+            HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, H5I_INVALID_HID, "can't close attribute")
+
     FUNC_LEAVE_API(ret_value)
-}   /* end H5Rget_region() */
+} /* end H5Ropen_attr() */
 
 
-/*--------------------------------------------------------------------------
- NAME
-    H5Rget_obj_type2
- PURPOSE
-    Retrieves the type of object that an object reference points to
- USAGE
-    herr_t H5Rget_obj_type2(id, ref_type, ref, obj_type)
-        hid_t id;       IN: Dataset reference object is in or location ID of
-                            object that the dataset is located within.
-        H5R_type_t ref_type;    IN: Type of reference to query
-        void *ref;          IN: Reference to query.
-        H5O_type_t *obj_type;   OUT: Type of object reference points to
-
- RETURNS
-    Non-negative on success/Negative on failure
- DESCRIPTION
-    Given a reference to some object, this function retrieves the type of
-    object pointed to.
- GLOBAL VARIABLES
- COMMENTS, BUGS, ASSUMPTIONS
- EXAMPLES
- REVISION LOG
---------------------------------------------------------------------------*/
+/*-------------------------------------------------------------------------
+ * Function:    H5Rget_obj_type3
+ *
+ * Purpose: Given a reference to some object, this function returns the type
+ * of object pointed to.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
 herr_t
-H5Rget_obj_type2(hid_t id, H5R_type_t ref_type, const void *ref,
-    H5O_type_t *obj_type)
+H5Rget_obj_type3(const H5R_ref_t *ref_ptr, hid_t rapl_id, H5O_type_t *obj_type)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    herr_t ret_value = SUCCEED; /* Return value */
+    hid_t loc_id;                       /* Reference location ID */
+    H5VL_object_t *vol_obj = NULL;      /* Object token of loc_id */
+    H5VL_loc_params_t loc_params;       /* Location parameters */
+    H5VL_token_t obj_token = {0};       /* Object token */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE4("e", "iRt*x*Ot", id, ref_type, ref, obj_type);
+    H5TRACE3("e", "*Rri*Ot", ref_ptr, rapl_id, obj_type);
 
     /* Check args */
-    if(ref_type <= H5R_BADTYPE || ref_type >= H5R_MAXTYPE)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference type")
-    if(ref == NULL)
+    if(ref_ptr == NULL)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference pointer")
+    if(H5R__get_type((const H5R_ref_priv_t *)ref_ptr) <= H5R_BADTYPE
+        || H5R__get_type((const H5R_ref_priv_t *)ref_ptr) >= H5R_MAXTYPE)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid reference type")
+    if(rapl_id < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a property list")
 
-    /* Set location parameters */
-    loc_params.type         = H5VL_OBJECT_BY_SELF;
-    loc_params.obj_type     = H5I_get_type(id);
+    /* Retrieve loc_id from reference */
+    if(H5I_INVALID_HID == (loc_id = H5R__get_loc_id((const H5R_ref_priv_t *)ref_ptr))) {
+        /* Attempt to re-open file and pass rapl_id as a fapl_id */
+        if((loc_id = H5R__reopen_file((H5R_ref_priv_t *)ref_ptr, rapl_id)) < 0)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENFILE, FAIL, "cannot re-open referenced file")
+    }
+
+    /* Get object token */
+    if(H5R__get_obj_token((const H5R_ref_priv_t *)ref_ptr, &obj_token, NULL) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to get object token")
 
-    /* Get the file object */
-    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object(id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
+    /* Get the VOL object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+    /* Set location parameters */
+    loc_params.type = H5VL_OBJECT_BY_TOKEN;
+    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.obj_type = H5I_get_type(loc_id);
 
-    /* Get the object type */
-    if(H5VL_object_get(vol_obj, &loc_params, H5VL_REF_GET_TYPE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, obj_type, (int)ref_type, ref) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to determine object type")
+    /* Retrieve object's type */
+    if(H5VL_object_get(vol_obj, &loc_params, H5VL_OBJECT_GET_TYPE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, obj_type) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, FAIL, "can't retrieve object type")
 
 done:
     FUNC_LEAVE_API(ret_value)
-}   /* end H5Rget_obj_type2() */
+} /* end H5Rget_obj_type3() */
 
 
-/*--------------------------------------------------------------------------
- NAME
-    H5Rget_name
- PURPOSE
-    Determines a name for the object referenced
- USAGE
-    ssize_t H5Rget_name(loc_id, ref_type, ref, name, size)
-        hid_t loc_id;   IN: Dataset reference object is in or location ID of
-                            object that the dataset is located within.
-        H5R_type_t ref_type;    IN: Type of reference
-        void *ref;      IN: Reference to query.
-        char *name;     OUT: Buffer to place name of object referenced. If NULL
-	                     then this call will return the size in bytes of name.
-        size_t size;    IN: Size of name buffer (user needs to include NULL terminator
-                            when passing in the size)
-
- RETURNS
-    Non-negative length of the path on success, -1 on failure
- DESCRIPTION
-    Given a reference to some object, determine a path to the object
-    referenced in the file.
- GLOBAL VARIABLES
- COMMENTS, BUGS, ASSUMPTIONS
-    This may not be the only path to that object.
- EXAMPLES
- REVISION LOG
-    M. Scot Breitenfeld
-    22 January 2014
-    Changed the behavior for the returned value of the function when name is NULL.
-    If name is NULL then size is ignored and the function returns the size 
-    of the name buffer (not including the NULL terminator), it still returns
-    negative on failure.
---------------------------------------------------------------------------*/
+/*-------------------------------------------------------------------------
+ * Function:    H5Rget_file_name
+ *
+ * Purpose: Given a reference to some object, determine a file name of the
+ * object located into.
+ *
+ * Return:  Non-negative length of the path on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
 ssize_t
-H5Rget_name(hid_t id, H5R_type_t ref_type, const void *_ref, char *name,
-    size_t size)
+H5Rget_file_name(const H5R_ref_t *ref_ptr, char *buf, size_t size)
 {
-    H5VL_object_t    *vol_obj = NULL;       /* object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    ssize_t ret_value = -1;             /* Return value */
+    hid_t loc_id;       /* Reference location ID */
+    ssize_t ret_value;  /* Return value */
 
     FUNC_ENTER_API((-1))
-    H5TRACE5("Zs", "iRt*x*sz", id, ref_type, _ref, name, size);
+    H5TRACE3("Zs", "*Rr*sz", ref_ptr, buf, size);
 
     /* Check args */
-    if(ref_type <= H5R_BADTYPE || ref_type >= H5R_MAXTYPE)
+    if(ref_ptr == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, (-1), "invalid reference pointer")
+    if(H5R__get_type((const H5R_ref_priv_t *)ref_ptr) <= H5R_BADTYPE
+        || H5R__get_type((const H5R_ref_priv_t *)ref_ptr) >= H5R_MAXTYPE)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, (-1), "invalid reference type")
-    if(_ref == NULL)
+
+    /* Get name */
+    if(H5I_INVALID_HID == (loc_id = H5R__get_loc_id((const H5R_ref_priv_t *)ref_ptr))) {
+        /* Un-opened external references do not have loc_id set but hold a
+         * copy of the filename */
+        if((ret_value = H5R__get_file_name((const H5R_ref_priv_t *)ref_ptr, buf, size)) < 0)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, (-1), "unable to retrieve file name")
+    } else {
+        H5VL_object_t *vol_obj = NULL;  /* Object token of loc_id */
+
+        /* Retrieve VOL file object */
+        if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, (-1), "invalid location identifier")
+
+        if(H5VL_file_get(vol_obj, H5VL_FILE_GET_NAME, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5I_FILE, size, buf, &ret_value) < 0)
+                HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, (-1), "unable to get file name")
+    }
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Rget_file_name() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Rget_obj_name
+ *
+ * Purpose: Given a reference to some object, determine a path to the object
+ * referenced in the file.
+ *
+ * Return:  Non-negative length of the path on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+ssize_t
+H5Rget_obj_name(const H5R_ref_t *ref_ptr, hid_t rapl_id, char *buf, size_t size)
+{
+    hid_t loc_id;                       /* Reference location ID */
+    H5VL_object_t *vol_obj = NULL;      /* Object token of loc_id */
+    H5VL_loc_params_t loc_params;       /* Location parameters */
+    H5VL_token_t obj_token = {0};       /* Object token */
+    ssize_t ret_value;                  /* Return value */
+
+    FUNC_ENTER_API((-1))
+    H5TRACE4("Zs", "*Rri*sz", ref_ptr, rapl_id, buf, size);
+
+    /* Check args */
+    if(ref_ptr == NULL)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, (-1), "invalid reference pointer")
+    if(H5R__get_type((const H5R_ref_priv_t *)ref_ptr) <= H5R_BADTYPE
+        || H5R__get_type((const H5R_ref_priv_t *)ref_ptr) >= H5R_MAXTYPE)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, (-1), "invalid reference type")
+    if(rapl_id < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a property list")
 
-    /* Set location parameters */
-    loc_params.type = H5VL_OBJECT_BY_SELF;
-    loc_params.obj_type = H5I_get_type(id);
+    /* Retrieve loc_id from reference */
+    if(H5I_INVALID_HID == (loc_id = H5R__get_loc_id((const H5R_ref_priv_t *)ref_ptr))) {
+        /* Attempt to re-open file and pass rapl_id as a fapl_id */
+        if((loc_id = H5R__reopen_file((H5R_ref_priv_t *)ref_ptr, rapl_id)) < 0)
+            HGOTO_ERROR(H5E_REFERENCE, H5E_CANTOPENFILE, (-1), "cannot re-open referenced file")
+    }
 
-    /* Get the file object */
-    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object(id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, (-1), "invalid file identifier")
+    /* Get object token */
+    if((ret_value = H5R__get_obj_token((const H5R_ref_priv_t *)ref_ptr, &obj_token, NULL)) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, (-1), "unable to get object token")
 
-    /* Get name */
-    if(H5VL_object_get(vol_obj, &loc_params, H5VL_REF_GET_NAME, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &ret_value, name, size, (int)ref_type, _ref) < 0)
-        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, (-1), "unable to determine object path")
+    /* Get the VOL object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, (-1), "invalid location identifier")
+
+    /* Set location parameters */
+    loc_params.type = H5VL_OBJECT_BY_TOKEN;
+    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.obj_type = H5I_get_type(loc_id);
+
+    /* Retrieve object's name */
+    if(H5VL_object_get(vol_obj, &loc_params, H5VL_OBJECT_GET_NAME, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &ret_value, buf, size) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, (-1), "can't retrieve object name")
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* end H5Rget_name() */
+} /* end H5Rget_obj_name() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Rget_attr_name
+ *
+ * Purpose: Given a reference to some attribute, determine its name.
+ *
+ * Return:  Non-negative length of the path on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+ssize_t
+H5Rget_attr_name(const H5R_ref_t *ref_ptr, char *buf, size_t size)
+{
+    ssize_t ret_value;  /* Return value */
+
+    FUNC_ENTER_API((-1))
+    H5TRACE3("Zs", "*Rr*sz", ref_ptr, buf, size);
+
+    /* Check args */
+    if(ref_ptr == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, (-1), "invalid reference pointer")
+    if(H5R__get_type((const H5R_ref_priv_t *)ref_ptr) != H5R_ATTR)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, (-1), "invalid reference type")
+
+    /* Get attribute name */
+    if((ret_value = H5R__get_attr_name((const H5R_ref_priv_t *)ref_ptr, buf, size)) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, (-1), "unable to determine attribute name")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Rget_attr_name() */