Merge pull request #1580 in HDFFV/hdf5 from update_vol_callbacks to develop

* commit 'd6663b95ac7e9e378b24bd721ea4403ca98d4adf':
  Revise "management" VOL callbacks into 'info' and object 'wrap / retrieval' classes.

8 files changed, 170 insertions, 140 deletions

diff --git a/src/H5Pfapl.c b/src/H5Pfapl.c
index 452ea3f..bfb52ff 100644
--- a/src/H5Pfapl.c
+++ b/src/H5Pfapl.c
@@ -5231,7 +5231,7 @@ H5P__facc_vol_cmp(const void *_info1, const void *_info2, size_t H5_ATTR_UNUSED
     /* Use one of the classes (cls1) info comparison routines to compare the
      * info objects
      */
-    HDassert(cls1->info_cmp == cls2->info_cmp);
+    HDassert(cls1->info_cls.cmp == cls2->info_cls.cmp);
     status = H5VL_cmp_connector_info(cls1, &cmp_value, info1->connector_info, info2->connector_info);
     HDassert(status >= 0);
 
diff --git a/src/H5VL.c b/src/H5VL.c
index 37ad187..aa276ec 100644
--- a/src/H5VL.c
+++ b/src/H5VL.c
@@ -156,9 +156,9 @@ H5VLregister_connector(const H5VL_class_t *cls, hid_t vipl_id)
         HGOTO_ERROR(H5E_VOL, H5E_CANTREGISTER, H5I_INVALID_HID, "VOL connector class name cannot be the NULL pointer")
     if (0 == HDstrlen(cls->name))
         HGOTO_ERROR(H5E_VOL, H5E_CANTREGISTER, H5I_INVALID_HID, "VOL connector class name cannot be the empty string")
-    if (cls->info_copy && !cls->info_free)
+    if (cls->info_cls.copy && !cls->info_cls.free)
         HGOTO_ERROR(H5E_VOL, H5E_CANTREGISTER, H5I_INVALID_HID, "VOL connector must provide free callback for VOL info objects when a copy callback is provided")
-    if (cls->get_wrap_ctx && !cls->free_wrap_ctx)
+    if (cls->wrap_cls.get_wrap_ctx && !cls->wrap_cls.free_wrap_ctx)
         HGOTO_ERROR(H5E_VOL, H5E_CANTREGISTER, H5I_INVALID_HID, "VOL connector must provide free callback for object wrapping contexts when a get callback is provided")
 
     op_data.kind = H5VL_GET_CONNECTOR_BY_NAME;
diff --git a/src/H5VLcallback.c b/src/H5VLcallback.c
index e1030b2..5a5d9ee 100644
--- a/src/H5VLcallback.c
+++ b/src/H5VLcallback.c
@@ -348,14 +348,14 @@ H5VL_copy_connector_info(const H5VL_class_t *connector, void **dst_info,
     /* Check for actual source info */
     if(src_info) {
         /* Allow the connector to copy or do it ourselves */
-        if(connector->info_copy) {
-            if(NULL == (new_connector_info = (connector->info_copy)(src_info)))
+        if(connector->info_cls.copy) {
+            if(NULL == (new_connector_info = (connector->info_cls.copy)(src_info)))
                 HGOTO_ERROR(H5E_VOL, H5E_CANTCOPY, FAIL, "connector info copy callback failed")
         } /* end if */
-        else if(connector->info_size > 0) {
-            if(NULL == (new_connector_info = H5MM_malloc(connector->info_size)))
+        else if(connector->info_cls.size > 0) {
+            if(NULL == (new_connector_info = H5MM_malloc(connector->info_cls.size)))
                 HGOTO_ERROR(H5E_VOL, H5E_CANTALLOC, FAIL, "connector info allocation failed")
-            HDmemcpy(new_connector_info, src_info, connector->info_size);
+            HDmemcpy(new_connector_info, src_info, connector->info_cls.size);
         } /* end else-if */
         else
             HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "no way to copy connector info")
@@ -444,13 +444,13 @@ H5VL_cmp_connector_info(const H5VL_class_t *connector, int *cmp_value,
      * if there is a a callback, otherwise just compare the info objects as
      * memory buffers
      */
-    if(connector->info_cmp) {
-        if((connector->info_cmp)(cmp_value, info1, info2) < 0)
+    if(connector->info_cls.cmp) {
+        if((connector->info_cls.cmp)(cmp_value, info1, info2) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTCOMPARE, FAIL, "can't compare connector info")
     } /* end if */
     else {
-        HDassert(connector->info_size > 0);
-        *cmp_value = HDmemcmp(info1, info2, connector->info_size);
+        HDassert(connector->info_cls.size > 0);
+        *cmp_value = HDmemcmp(info1, info2, connector->info_cls.size);
     } /* end else */
 
 done:
@@ -518,8 +518,8 @@ H5VL_free_connector_info(const H5VL_class_t *connector, void *info)
     /* Only free info object, if it's non-NULL */
     if(info) {
         /* Allow the connector to free info or do it ourselves */
-        if(connector->info_free) {
-            if((connector->info_free)(info) < 0)
+        if(connector->info_cls.free) {
+            if((connector->info_cls.free)(info) < 0)
                 HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "connector info free request failed")
         } /* end if */
         else
@@ -590,8 +590,8 @@ H5VLconnector_info_to_str(const void *info, hid_t connector_id, char **str)
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL connector ID")
 
         /* Allow the connector to serialize info */
-        if(cls->info_to_str) {
-            if((cls->info_to_str)(info, str) < 0)
+        if(cls->info_cls.to_str) {
+            if((cls->info_cls.to_str)(info, str) < 0)
                 HGOTO_ERROR(H5E_VOL, H5E_CANTSERIALIZE, FAIL, "can't serialize connector info")
         } /* end if */
         else
@@ -632,8 +632,8 @@ H5VLconnector_str_to_info(const char *str, hid_t connector_id, void **info)
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL connector ID")
 
         /* Allow the connector to deserialize info */
-        if(cls->str_to_info) {
-            if((cls->str_to_info)(str, info) < 0)
+        if(cls->info_cls.from_str) {
+            if((cls->info_cls.from_str)(str, info) < 0)
                 HGOTO_ERROR(H5E_VOL, H5E_CANTUNSERIALIZE, FAIL, "can't deserialize connector info")
         } /* end if */
         else
@@ -673,8 +673,8 @@ H5VLget_object(void *obj, hid_t connector_id)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a VOL connector ID")
 
     /* Check for 'get_object' callback in connector */
-    if(cls->get_object)
-        ret_value = (cls->get_object)(obj);
+    if(cls->wrap_cls.get_object)
+        ret_value = (cls->wrap_cls.get_object)(obj);
     else
         ret_value = obj;
 
@@ -706,12 +706,12 @@ H5VL_get_wrap_ctx(const H5VL_class_t *connector, void *obj, void **wrap_ctx)
     HDassert(wrap_ctx);
 
     /* Allow the connector to copy or do it ourselves */
-    if(connector->get_wrap_ctx) {
+    if(connector->wrap_cls.get_wrap_ctx) {
         /* Sanity check */
-        HDassert(connector->free_wrap_ctx);
+        HDassert(connector->wrap_cls.free_wrap_ctx);
 
         /* Invoke connector's callback */
-        if((connector->get_wrap_ctx)(obj, wrap_ctx) < 0)
+        if((connector->wrap_cls.get_wrap_ctx)(obj, wrap_ctx) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "connector wrap context callback failed")
     } /* end if */
     else
@@ -777,7 +777,7 @@ H5VL_free_wrap_ctx(const H5VL_class_t *connector, void *wrap_ctx)
     /* Only free wrap context, if it's non-NULL */
     if(wrap_ctx) {
         /* Free the connector's object wrapping context */
-        if((connector->free_wrap_ctx)(wrap_ctx) < 0)
+        if((connector->wrap_cls.free_wrap_ctx)(wrap_ctx) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "connector wrap context free request failed")
     } /* end if */
 
@@ -843,7 +843,7 @@ H5VL_wrap_object(const H5VL_class_t *connector, void *wrap_ctx, void *obj,
     /* Only wrap object if there's a wrap context */
     if(wrap_ctx) {
         /* Ask the connector to wrap the object */
-        if(NULL == (ret_value = (connector->wrap_object)(obj, obj_type, wrap_ctx)))
+        if(NULL == (ret_value = (connector->wrap_cls.wrap_object)(obj, obj_type, wrap_ctx)))
             HGOTO_ERROR(H5E_VOL, H5E_CANTGET, NULL, "can't wrap object")
     } /* end if */
     else
diff --git a/src/H5VLint.c b/src/H5VLint.c
index f22fdb6..5aa25d2 100644
--- a/src/H5VLint.c
+++ b/src/H5VLint.c
@@ -740,8 +740,8 @@ H5VL_object_data(const H5VL_object_t *vol_obj)
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
     /* Check for 'get_object' callback in connector */
-    if(vol_obj->connector->cls->get_object)
-        ret_value = (vol_obj->connector->cls->get_object)(vol_obj->data);
+    if(vol_obj->connector->cls->wrap_cls.get_object)
+        ret_value = (vol_obj->connector->cls->wrap_cls.get_object)(vol_obj->data);
     else
         ret_value = vol_obj->data;
 
@@ -933,15 +933,15 @@ H5VL_cmp_connector_cls(int *cmp_value, const H5VL_class_t *cls1, const H5VL_clas
     HDassert(cls1->version == cls2->version);
 
     /* Compare connector info */
-    if(cls1->info_size < cls2->info_size) {
+    if(cls1->info_cls.size < cls2->info_cls.size) {
         *cmp_value = -1;
         HGOTO_DONE(SUCCEED)
     } /* end if */
-    if(cls1->info_size > cls2->info_size) {
+    if(cls1->info_cls.size > cls2->info_cls.size) {
         *cmp_value = 1;
         HGOTO_DONE(SUCCEED)
     } /* end if */
-    HDassert(cls1->info_size == cls2->info_size);
+    HDassert(cls1->info_cls.size == cls2->info_cls.size);
 
     /* Set comparison value to 'equal' */
     *cmp_value = 0;
@@ -980,12 +980,12 @@ H5VL_set_vol_wrapper(void *obj, const H5VL_t *connector)
     /* Check for existing wrapping context */
     if(NULL == vol_wrap_ctx) {
         /* Check if the connector can create a wrap context */
-        if(connector->cls->get_wrap_ctx) {
+        if(connector->cls->wrap_cls.get_wrap_ctx) {
             /* Sanity check */
-            HDassert(connector->cls->free_wrap_ctx);
+            HDassert(connector->cls->wrap_cls.free_wrap_ctx);
 
             /* Get the wrap context from the connector */
-            if((connector->cls->get_wrap_ctx)(obj, &obj_wrap_ctx) < 0)
+            if((connector->cls->wrap_cls.get_wrap_ctx)(obj, &obj_wrap_ctx) < 0)
                 HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't retrieve VOL connector's object wrap context")
         } /* end if */
 
@@ -1048,7 +1048,7 @@ H5VL_reset_vol_wrapper(void)
         /* If there is a VOL connector object wrapping context, release it */
         if(vol_wrap_ctx->obj_wrap_ctx) {
             /* Release the VOL connector's object wrapping context */
-            if((*vol_wrap_ctx->connector->cls->free_wrap_ctx)(vol_wrap_ctx->obj_wrap_ctx) < 0)
+            if((*vol_wrap_ctx->connector->cls->wrap_cls.free_wrap_ctx)(vol_wrap_ctx->obj_wrap_ctx) < 0)
                 HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to release connector's object wrapping context")
         } /* end if */
 
diff --git a/src/H5VLnative.c b/src/H5VLnative.c
index fe0fd4e..f4f3b5f 100644
--- a/src/H5VLnative.c
+++ b/src/H5VLnative.c
@@ -38,16 +38,20 @@ static H5VL_class_t H5VL_native_cls_g = {
     0,                                              /* capability flags */
     NULL,                                           /* initialize   */
     H5VL__native_term,                              /* terminate    */
-    (size_t)0,                                      /* info size    */
-    NULL,                                           /* info copy    */
-    NULL,                                           /* info compare */
-    NULL,                                           /* info free    */
-    NULL,                                           /* info to str  */
-    NULL,                                           /* str to info  */
-    NULL,                                           /* get_object   */
-    NULL,                                           /* get_wrap_ctx */
-    NULL,                                           /* wrap_object  */
-    NULL,                                           /* free_wrap_ctx */
+    {   /* info_cls */
+        (size_t)0,                                  /* info size    */
+        NULL,                                       /* info copy    */
+        NULL,                                       /* info compare */
+        NULL,                                       /* info free    */
+        NULL,                                       /* info to str  */
+        NULL                                        /* str to info  */
+    },
+    {   /* wrap_cls */
+        NULL,                                       /* get_object   */
+        NULL,                                       /* get_wrap_ctx */
+        NULL,                                       /* wrap_object  */
+        NULL                                        /* free_wrap_ctx */
+    },
     {   /* attribute_cls */
         H5VL__native_attr_create,                   /* create       */
         H5VL__native_attr_open,                     /* open         */
diff --git a/src/H5VLpassthru.c b/src/H5VLpassthru.c
index f7f9058..fe72000 100644
--- a/src/H5VLpassthru.c
+++ b/src/H5VLpassthru.c
@@ -82,11 +82,15 @@ static herr_t H5VL_pass_through_free_obj(H5VL_pass_through_t *obj);
 /* "Management" callbacks */
 static herr_t H5VL_pass_through_init(hid_t vipl_id);
 static herr_t H5VL_pass_through_term(void);
+
+/* VOL info callbacks */
 static void *H5VL_pass_through_info_copy(const void *info);
 static herr_t H5VL_pass_through_info_cmp(int *cmp_value, const void *info1, const void *info2);
 static herr_t H5VL_pass_through_info_free(void *info);
 static herr_t H5VL_pass_through_info_to_str(const void *info, char **str);
 static herr_t H5VL_pass_through_str_to_info(const char *str, void **info);
+
+/* VOL object wrap / retrieval callbacks */
 static void *H5VL_pass_through_get_object(const void *obj);
 static herr_t H5VL_pass_through_get_wrap_ctx(const void *obj, void **wrap_ctx);
 static herr_t H5VL_pass_through_free_wrap_ctx(void *obj);
@@ -173,82 +177,86 @@ static const H5VL_class_t H5VL_pass_through_g = {
     0,                                              /* capability flags */
     H5VL_pass_through_init,                         /* initialize   */
     H5VL_pass_through_term,                         /* terminate    */
-    sizeof(H5VL_pass_through_info_t),               /* info size    */
-    H5VL_pass_through_info_copy,                    /* info copy    */
-    H5VL_pass_through_info_cmp,                     /* info compare */
-    H5VL_pass_through_info_free,                    /* info free    */
-    H5VL_pass_through_info_to_str,                  /* info to str  */
-    H5VL_pass_through_str_to_info,                  /* str to info  */
-    H5VL_pass_through_get_object,                   /* get_object   */
-    H5VL_pass_through_get_wrap_ctx,                 /* get_wrap_ctx */
-    H5VL_pass_through_wrap_object,                  /* wrap_object  */
-    H5VL_pass_through_free_wrap_ctx,                /* free_wrap_ctx */
+    {                                           /* info_cls */
+        sizeof(H5VL_pass_through_info_t),           /* size    */
+        H5VL_pass_through_info_copy,                /* copy    */
+        H5VL_pass_through_info_cmp,                 /* compare */
+        H5VL_pass_through_info_free,                /* free    */
+        H5VL_pass_through_info_to_str,              /* to_str  */
+        H5VL_pass_through_str_to_info,              /* from_str */
+    },
+    {                                           /* wrap_cls */
+        H5VL_pass_through_get_object,               /* get_object   */
+        H5VL_pass_through_get_wrap_ctx,             /* get_wrap_ctx */
+        H5VL_pass_through_wrap_object,              /* wrap_object  */
+        H5VL_pass_through_free_wrap_ctx,            /* free_wrap_ctx */
+    },
     {                                           /* attribute_cls */
-        H5VL_pass_through_attr_create,                       /* create */
-        H5VL_pass_through_attr_open,                         /* open */
-        H5VL_pass_through_attr_read,                         /* read */
-        H5VL_pass_through_attr_write,                        /* write */
-        H5VL_pass_through_attr_get,                          /* get */
-        H5VL_pass_through_attr_specific,                     /* specific */
-        H5VL_pass_through_attr_optional,                     /* optional */
-        H5VL_pass_through_attr_close                         /* close */
+        H5VL_pass_through_attr_create,              /* create */
+        H5VL_pass_through_attr_open,                /* open */
+        H5VL_pass_through_attr_read,                /* read */
+        H5VL_pass_through_attr_write,               /* write */
+        H5VL_pass_through_attr_get,                 /* get */
+        H5VL_pass_through_attr_specific,            /* specific */
+        H5VL_pass_through_attr_optional,            /* optional */
+        H5VL_pass_through_attr_close                /* close */
     },
     {                                           /* dataset_cls */
-        H5VL_pass_through_dataset_create,                    /* create */
-        H5VL_pass_through_dataset_open,                      /* open */
-        H5VL_pass_through_dataset_read,                      /* read */
-        H5VL_pass_through_dataset_write,                     /* write */
-        H5VL_pass_through_dataset_get,                       /* get */
-        H5VL_pass_through_dataset_specific,                  /* specific */
-        H5VL_pass_through_dataset_optional,                  /* optional */
-        H5VL_pass_through_dataset_close                      /* close */
+        H5VL_pass_through_dataset_create,           /* create */
+        H5VL_pass_through_dataset_open,             /* open */
+        H5VL_pass_through_dataset_read,             /* read */
+        H5VL_pass_through_dataset_write,            /* write */
+        H5VL_pass_through_dataset_get,              /* get */
+        H5VL_pass_through_dataset_specific,         /* specific */
+        H5VL_pass_through_dataset_optional,         /* optional */
+        H5VL_pass_through_dataset_close             /* close */
     },
-    {                                               /* datatype_cls */
-        H5VL_pass_through_datatype_commit,                   /* commit */
-        H5VL_pass_through_datatype_open,                     /* open */
-        H5VL_pass_through_datatype_get,                      /* get_size */
-        H5VL_pass_through_datatype_specific,                 /* specific */
-        H5VL_pass_through_datatype_optional,                 /* optional */
-        H5VL_pass_through_datatype_close                     /* close */
+    {                                           /* datatype_cls */
+        H5VL_pass_through_datatype_commit,          /* commit */
+        H5VL_pass_through_datatype_open,            /* open */
+        H5VL_pass_through_datatype_get,             /* get_size */
+        H5VL_pass_through_datatype_specific,        /* specific */
+        H5VL_pass_through_datatype_optional,        /* optional */
+        H5VL_pass_through_datatype_close            /* close */
     },
     {                                           /* file_cls */
-        H5VL_pass_through_file_create,                       /* create */
-        H5VL_pass_through_file_open,                         /* open */
-        H5VL_pass_through_file_get,                          /* get */
-        H5VL_pass_through_file_specific,                     /* specific */
-        H5VL_pass_through_file_optional,                     /* optional */
-        H5VL_pass_through_file_close                         /* close */
+        H5VL_pass_through_file_create,              /* create */
+        H5VL_pass_through_file_open,                /* open */
+        H5VL_pass_through_file_get,                 /* get */
+        H5VL_pass_through_file_specific,            /* specific */
+        H5VL_pass_through_file_optional,            /* optional */
+        H5VL_pass_through_file_close                /* close */
     },
     {                                           /* group_cls */
-        H5VL_pass_through_group_create,                      /* create */
-        H5VL_pass_through_group_open,                        /* open */
-        H5VL_pass_through_group_get,                         /* get */
-        H5VL_pass_through_group_specific,                    /* specific */
-        H5VL_pass_through_group_optional,                    /* optional */
-        H5VL_pass_through_group_close                        /* close */
+        H5VL_pass_through_group_create,             /* create */
+        H5VL_pass_through_group_open,               /* open */
+        H5VL_pass_through_group_get,                /* get */
+        H5VL_pass_through_group_specific,           /* specific */
+        H5VL_pass_through_group_optional,           /* optional */
+        H5VL_pass_through_group_close               /* close */
     },
     {                                           /* link_cls */
-        H5VL_pass_through_link_create,                       /* create */
-        H5VL_pass_through_link_copy,                         /* copy */
-        H5VL_pass_through_link_move,                         /* move */
-        H5VL_pass_through_link_get,                          /* get */
-        H5VL_pass_through_link_specific,                     /* specific */
-        H5VL_pass_through_link_optional,                     /* optional */
+        H5VL_pass_through_link_create,              /* create */
+        H5VL_pass_through_link_copy,                /* copy */
+        H5VL_pass_through_link_move,                /* move */
+        H5VL_pass_through_link_get,                 /* get */
+        H5VL_pass_through_link_specific,            /* specific */
+        H5VL_pass_through_link_optional,            /* optional */
     },
     {                                           /* object_cls */
-        H5VL_pass_through_object_open,                       /* open */
-        H5VL_pass_through_object_copy,                       /* copy */
-        H5VL_pass_through_object_get,                        /* get */
-        H5VL_pass_through_object_specific,                   /* specific */
-        H5VL_pass_through_object_optional,                   /* optional */
+        H5VL_pass_through_object_open,              /* open */
+        H5VL_pass_through_object_copy,              /* copy */
+        H5VL_pass_through_object_get,               /* get */
+        H5VL_pass_through_object_specific,          /* specific */
+        H5VL_pass_through_object_optional,          /* optional */
     },
     {                                           /* request_cls */
-        H5VL_pass_through_request_wait,                      /* wait */
-        H5VL_pass_through_request_notify,                    /* notify */
-        H5VL_pass_through_request_cancel,                    /* cancel */
-        H5VL_pass_through_request_specific,                  /* specific */
-        H5VL_pass_through_request_optional,                  /* optional */
-        H5VL_pass_through_request_free                       /* free */
+        H5VL_pass_through_request_wait,             /* wait */
+        H5VL_pass_through_request_notify,           /* notify */
+        H5VL_pass_through_request_cancel,           /* cancel */
+        H5VL_pass_through_request_specific,         /* specific */
+        H5VL_pass_through_request_optional,         /* optional */
+        H5VL_pass_through_request_free              /* free */
     },
     NULL                                        /* optional */
 };
diff --git a/src/H5VLpublic.h b/src/H5VLpublic.h
index 6ea9fc1..72e69b8 100644
--- a/src/H5VLpublic.h
+++ b/src/H5VLpublic.h
@@ -236,6 +236,25 @@ typedef struct H5VL_loc_params_t {
     } loc_data;
 } H5VL_loc_params_t;
 
+/* VOL connector info fields & callbacks */
+typedef struct H5VL_info_class_t {
+    size_t size;                                    /* Size of the VOL info                         */
+    void * (*copy)(const void *info);               /* Callback to create a copy of the VOL info    */
+    herr_t (*cmp)(int *cmp_value, const void *info1, const void *info2); /* Callback to compare VOL info */
+    herr_t (*free)(void *info);                     /* Callback to release a VOL info               */
+    herr_t (*to_str)(const void *info, char **str); /* Callback to serialize connector's info into a string */
+    herr_t (*from_str)(const char *str, void **info); /* Callback to deserialize a string into connector's info */
+} H5VL_info_class_t;
+
+/* VOL object wrap / retrieval callbacks */
+/* (These only need to be implemented by "pass through" VOL connectors) */
+typedef struct H5VL_wrap_class_t {
+    void * (*get_object)(const void *obj);          /* Callback to retrieve underlying object       */
+    herr_t (*get_wrap_ctx)(const void *obj, void **wrap_ctx); /* Callback to retrieve the object wrapping context for the connector */
+    void * (*wrap_object)(void *obj, H5I_type_t obj_type, void *wrap_ctx); /* Callback to wrap a library object */
+    herr_t (*free_wrap_ctx)(void *wrap_ctx);        /* Callback to release the object wrapping context for the connector */
+} H5VL_wrap_class_t;
+
 /* H5A routines */
 typedef struct H5VL_attr_class_t {
     void *(*create)(void *obj, const H5VL_loc_params_t *loc_params, const char *attr_name,
@@ -370,34 +389,29 @@ typedef int H5VL_class_value_t;
 
 /* Class information for each VOL connector */
 typedef struct H5VL_class_t {
-    unsigned int version;                           /* VOL connector class struct version #         */
-    H5VL_class_value_t value;                       /* Value to identify connector                  */
-    const char *name;                               /* Connector name (MUST be unique!)             */
-    unsigned cap_flags;                             /* Capability flags for connector               */
-    herr_t  (*initialize)(hid_t vipl_id);           /* Connector initialization callback            */
-    herr_t  (*terminate)(void);                     /* Connector termination callback               */
-    size_t  info_size;                              /* Size of the VOL info                         */
-    void *  (*info_copy)(const void *info);         /* Callback to create a copy of the VOL info    */
-    herr_t  (*info_cmp)(int *cmp_value, const void *info1, const void *info2); /* Callback to compare VOL info */
-    herr_t  (*info_free)(void *info);               /* Callback to release the VOL info copy        */
-    herr_t  (*info_to_str)(const void *info, char **str); /* Callback to serialize connector's info into a string */
-    herr_t  (*str_to_info)(const char *str, void **info); /* Callback to deserialize a string into connector's info */
-    void *  (*get_object)(const void *obj);         /* Callback to retrieve underlying object       */
-    herr_t  (*get_wrap_ctx)(const void *obj, void **wrap_ctx); /* Callback to retrieve the object wrapping context for the connector */
-    void*   (*wrap_object)(void *obj, H5I_type_t obj_type, void *wrap_ctx); /* Callback to wrap a library object */
-    herr_t  (*free_wrap_ctx)(void *wrap_ctx);       /* Callback to release the object wrapping context for the connector */
+    /* Overall connector fields & callbacks */
+    unsigned int version;                   /* VOL connector class struct version #     */
+    H5VL_class_value_t value;               /* Value to identify connector              */
+    const char *name;                       /* Connector name (MUST be unique!)         */
+    unsigned cap_flags;                     /* Capability flags for connector           */
+    herr_t (*initialize)(hid_t vipl_id);    /* Connector initialization callback        */
+    herr_t (*terminate)(void);              /* Connector termination callback           */
+
+    /* VOL framework */
+    H5VL_info_class_t       info_cls;       /* VOL info fields & callbacks  */
+    H5VL_wrap_class_t       wrap_cls;       /* VOL object wrap / retrieval callbacks */
 
     /* Data Model */
-    H5VL_attr_class_t          attr_cls;            /* attribute class callbacks    */
-    H5VL_dataset_class_t       dataset_cls;         /* dataset class callbacks      */
-    H5VL_datatype_class_t      datatype_cls;        /* datatype class callbacks     */
-    H5VL_file_class_t          file_cls;            /* file class callbacks         */
-    H5VL_group_class_t         group_cls;           /* group class callbacks        */
-    H5VL_link_class_t          link_cls;            /* link class callbacks         */
-    H5VL_object_class_t        object_cls;          /* object class callbacks       */
+    H5VL_attr_class_t       attr_cls;       /* Attribute (H5A*) class callbacks */
+    H5VL_dataset_class_t    dataset_cls;    /* Dataset (H5D*) class callbacks   */
+    H5VL_datatype_class_t   datatype_cls;   /* Datatype (H5T*) class callbacks  */
+    H5VL_file_class_t       file_cls;       /* File (H5F*) class callbacks      */
+    H5VL_group_class_t      group_cls;      /* Group (H5G*) class callbacks     */
+    H5VL_link_class_t       link_cls;       /* Link (H5L*) class callbacks      */
+    H5VL_object_class_t     object_cls;     /* Object (H5O*) class callbacks    */
 
     /* Services */
-    H5VL_request_class_t       request_cls;         /* asynchronous request class callbacks */
+    H5VL_request_class_t    request_cls;    /* Asynchronous request class callbacks */
 
     /* Catch-all */
     herr_t (*optional)(void *obj, hid_t dxpl_id, void **req, va_list arguments); /* Optional callback */
diff --git a/test/vol.c b/test/vol.c
index c55874a..e267084 100644
--- a/test/vol.c
+++ b/test/vol.c
@@ -49,16 +49,20 @@ static const H5VL_class_t fake_vol_g = {
     0,                                              /* capability flags */
     NULL,                                           /* initialize   */
     NULL,                                           /* terminate    */
-    (size_t)0,                                      /* info size    */
-    NULL,                                           /* info copy    */
-    NULL,                                           /* info compare */
-    NULL,                                           /* info free    */
-    NULL,                                           /* info to str  */
-    NULL,                                           /* str to info  */
-    NULL,                                           /* get_object   */
-    NULL,                                           /* get_wrap_ctx */
-    NULL,                                           /* wrap_object  */
-    NULL,                                           /* free_wrap_ctx */
+    {   /* info_cls */
+        (size_t)0,                                  /* size    */
+        NULL,                                       /* copy    */
+        NULL,                                       /* compare */
+        NULL,                                       /* free    */
+        NULL,                                       /* to_str  */
+        NULL,                                       /* from_str */
+    },
+    {   /* wrap_cls */
+        NULL,                                       /* get_object   */
+        NULL,                                       /* get_wrap_ctx */
+        NULL,                                       /* wrap_object  */
+        NULL,                                       /* free_wrap_ctx */
+    },
     {   /* attribute_cls */
         NULL,                                       /* create       */
         NULL,                                       /* open         */