Expand ID dec_ref and close callbacks to allow for asynchronous close operations (#135)

* Expand ID dec_ref and close callbacks to allow for asynchronous close operations.

* Fix typo

* Rename token -> request, remove programmer name

* H5E_ATOM to H5E_ID

19 files changed, 311 insertions, 79 deletions

diff --git a/src/H5A.c b/src/H5A.c
index ae54370..20d6107 100644
--- a/src/H5A.c
+++ b/src/H5A.c
@@ -1456,12 +1456,14 @@ H5Aclose(hid_t attr_id)
     H5TRACE1("e", "i", attr_id);
 
     /* Check arguments */
-    if (NULL == H5I_object_verify(attr_id, H5I_ATTR))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not an attribute")
+    if (H5I_ATTR != H5I_get_type(attr_id))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not an attribute ID")
 
-    /* Decrement references to that ID (and close it) */
+    /* Decrement the counter on the attribute ID. It will be freed if the count
+     * reaches zero.
+     */
     if (H5I_dec_app_ref(attr_id) < 0)
-        HGOTO_ERROR(H5E_ATTR, H5E_CANTDEC, FAIL, "can't close attribute")
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTDEC, FAIL, "decrementing attribute ID failed")
 
 done:
     FUNC_LEAVE_API(ret_value)
diff --git a/src/H5Aint.c b/src/H5Aint.c
index 5bc4a65..48e22ad 100644
--- a/src/H5Aint.c
+++ b/src/H5Aint.c
@@ -83,7 +83,7 @@ typedef struct {
 /* Local Prototypes */
 /********************/
 
-static herr_t H5A__close_cb(H5VL_object_t *attr_vol_obj);
+static herr_t H5A__close_cb(H5VL_object_t *attr_vol_obj, void **request);
 static herr_t H5A__compact_build_table_cb(H5O_t *oh, H5O_mesg_t *mesg /*in,out*/, unsigned sequence,
                                           unsigned *oh_flags_ptr, void *_udata /*in,out*/);
 static herr_t H5A__dense_build_table_cb(const H5A_t *attr, void *_udata);
@@ -1293,7 +1293,7 @@ H5A__shared_free(H5A_t *attr)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5A__close_cb(H5VL_object_t *attr_vol_obj)
+H5A__close_cb(H5VL_object_t *attr_vol_obj, void **request)
 {
     herr_t ret_value = SUCCEED; /* Return value */
 
@@ -1303,7 +1303,7 @@ H5A__close_cb(H5VL_object_t *attr_vol_obj)
     HDassert(attr_vol_obj);
 
     /* Close the attribute */
-    if ((ret_value = H5VL_attr_close(attr_vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)) < 0)
+    if ((ret_value = H5VL_attr_close(attr_vol_obj, H5P_DATASET_XFER_DEFAULT, request)) < 0)
         HGOTO_ERROR(H5E_ATTR, H5E_CLOSEERROR, FAIL, "problem closing attribute")
 
     /* Free the VOL object */
diff --git a/src/H5Dint.c b/src/H5Dint.c
index e7248eb..0da1e01 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -83,7 +83,7 @@ static herr_t H5D__build_file_prefix(const H5D_t *dset, H5F_prefix_open_t prefix
 static herr_t H5D__open_oid(H5D_t *dataset, hid_t dapl_id);
 static herr_t H5D__init_storage(const H5D_io_info_t *io_info, hbool_t full_overwrite, hsize_t old_dim[]);
 static herr_t H5D__append_flush_setup(H5D_t *dset, hid_t dapl_id);
-static herr_t H5D__close_cb(H5VL_object_t *dset_vol_obj);
+static herr_t H5D__close_cb(H5VL_object_t *dset_vol_obj, void **request);
 static herr_t H5D__use_minimized_dset_headers(H5F_t *file, hbool_t *minimize);
 static herr_t H5D__prepare_minimized_oh(H5F_t *file, H5D_t *dset, H5O_loc_t *oloc);
 static size_t H5D__calculate_minimum_header_size(H5F_t *file, H5D_t *dset, H5O_t *ohdr);
@@ -330,7 +330,7 @@ H5D_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5D__close_cb(H5VL_object_t *dset_vol_obj)
+H5D__close_cb(H5VL_object_t *dset_vol_obj, void **request)
 {
     herr_t ret_value = SUCCEED; /* Return value */
 
@@ -340,7 +340,7 @@ H5D__close_cb(H5VL_object_t *dset_vol_obj)
     HDassert(dset_vol_obj);
 
     /* Close the dataset */
-    if (H5VL_dataset_close(dset_vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
+    if (H5VL_dataset_close(dset_vol_obj, H5P_DATASET_XFER_DEFAULT, request) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to close dataset");
 
 done:
diff --git a/src/H5E.c b/src/H5E.c
index 6042048..2153549 100644
--- a/src/H5E.c
+++ b/src/H5E.c
@@ -76,14 +76,14 @@
 /* Static function declarations */
 static herr_t     H5E__set_default_auto(H5E_t *stk);
 static H5E_cls_t *H5E__register_class(const char *cls_name, const char *lib_name, const char *version);
-static herr_t     H5E__unregister_class(H5E_cls_t *cls);
+static herr_t     H5E__unregister_class(H5E_cls_t *cls, void **request);
 static ssize_t    H5E__get_class_name(const H5E_cls_t *cls, char *name, size_t size);
 static int        H5E__close_msg_cb(void *obj_ptr, hid_t obj_id, void *udata);
-static herr_t     H5E__close_msg(H5E_msg_t *err);
+static herr_t     H5E__close_msg(H5E_msg_t *err, void **request);
 static H5E_msg_t *H5E__create_msg(H5E_cls_t *cls, H5E_type_t msg_type, const char *msg);
 static H5E_t *    H5E__get_current_stack(void);
 static herr_t     H5E__set_current_stack(H5E_t *estack);
-static herr_t     H5E__close_stack(H5E_t *err_stack);
+static herr_t     H5E__close_stack(H5E_t *err_stack, void **request);
 static ssize_t    H5E__get_num(const H5E_t *err_stack);
 
 /*********************/
@@ -540,7 +540,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5E__unregister_class(H5E_cls_t *cls)
+H5E__unregister_class(H5E_cls_t *cls, void H5_ATTR_UNUSED **request)
 {
     herr_t ret_value = SUCCEED; /* Return value */
 
@@ -660,7 +660,7 @@ H5E__close_msg_cb(void *obj_ptr, hid_t obj_id, void *udata)
 
     /* Close the message if it is in the class being closed */
     if (err_msg->cls == cls) {
-        if (H5E__close_msg(err_msg) < 0)
+        if (H5E__close_msg(err_msg, NULL) < 0)
             HGOTO_ERROR(H5E_ERROR, H5E_CANTCLOSEOBJ, H5_ITER_ERROR, "unable to close error message")
         if (NULL == H5I_remove(obj_id))
             HGOTO_ERROR(H5E_ERROR, H5E_CANTREMOVE, H5_ITER_ERROR, "unable to remove error message")
@@ -715,7 +715,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5E__close_msg(H5E_msg_t *err)
+H5E__close_msg(H5E_msg_t *err, void H5_ATTR_UNUSED **request)
 {
     FUNC_ENTER_STATIC_NOERR
 
@@ -816,7 +816,7 @@ H5E__create_msg(H5E_cls_t *cls, H5E_type_t msg_type, const char *msg_str)
 
 done:
     if (!ret_value)
-        if (msg && H5E__close_msg(msg) < 0)
+        if (msg && H5E__close_msg(msg, NULL) < 0)
             HDONE_ERROR(H5E_ERROR, H5E_CANTCLOSEOBJ, NULL, "unable to close error message")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1163,7 +1163,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5E__close_stack(H5E_t *estack)
+H5E__close_stack(H5E_t *estack, void H5_ATTR_UNUSED **request)
 {
     FUNC_ENTER_STATIC_NOERR
 
diff --git a/src/H5F.c b/src/H5F.c
index 26c8ecb..6705a3c 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -706,7 +706,9 @@ H5Fclose(hid_t file_id)
     if (H5I_FILE != H5I_get_type(file_id))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file ID")
 
-    /* Close the file */
+    /* Synchronously decrement reference count on ID.
+     * When it reaches zero the file will be closed.
+     */
     if (H5I_dec_app_ref(file_id) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "decrementing file ID failed")
 
diff --git a/src/H5FD.c b/src/H5FD.c
index ab96691..d12bb57 100644
--- a/src/H5FD.c
+++ b/src/H5FD.c
@@ -54,7 +54,7 @@
 /********************/
 /* Local Prototypes */
 /********************/
-static herr_t H5FD__free_cls(H5FD_class_t *cls);
+static herr_t H5FD__free_cls(H5FD_class_t *cls, void **request);
 static herr_t H5FD__query(const H5FD_t *f, unsigned long *flags /*out*/);
 
 /*********************/
@@ -172,7 +172,7 @@ H5FD_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FD__free_cls(H5FD_class_t *cls)
+H5FD__free_cls(H5FD_class_t *cls, void H5_ATTR_UNUSED **request)
 {
     herr_t ret_value = SUCCEED;
 
diff --git a/src/H5Fint.c b/src/H5Fint.c
index 5e22ed8..92b70ce 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -72,7 +72,7 @@ typedef struct H5F_olist_t {
 /* Local Prototypes */
 /********************/
 
-static herr_t H5F__close_cb(H5VL_object_t *file_vol_obj);
+static herr_t H5F__close_cb(H5VL_object_t *file_vol_obj, void **request);
 static herr_t H5F__set_vol_conn(H5F_t *file);
 static herr_t H5F__get_objects(const H5F_t *f, unsigned types, size_t max_index, hid_t *obj_id_list,
                                hbool_t app_ref, size_t *obj_id_count_ptr);
@@ -234,7 +234,7 @@ H5F_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5F__close_cb(H5VL_object_t *file_vol_obj)
+H5F__close_cb(H5VL_object_t *file_vol_obj, void **request)
 {
     herr_t ret_value = SUCCEED; /* Return value */
 
@@ -244,7 +244,7 @@ H5F__close_cb(H5VL_object_t *file_vol_obj)
     HDassert(file_vol_obj);
 
     /* Close the file */
-    if (H5VL_file_close(file_vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
+    if (H5VL_file_close(file_vol_obj, H5P_DATASET_XFER_DEFAULT, request) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "unable to close file")
 
     /* Free the VOL object */
diff --git a/src/H5Gint.c b/src/H5Gint.c
index 3741067..56c4751 100644
--- a/src/H5Gint.c
+++ b/src/H5Gint.c
@@ -84,7 +84,7 @@ typedef struct {
 
 static herr_t H5G__open_oid(H5G_t *grp);
 static herr_t H5G__visit_cb(const H5O_link_t *lnk, void *_udata);
-static herr_t H5G__close_cb(H5VL_object_t *grp_vol_obj);
+static herr_t H5G__close_cb(H5VL_object_t *grp_vol_obj, void **request);
 
 /*********************/
 /* Package Variables */
@@ -263,7 +263,7 @@ H5G_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5G__close_cb(H5VL_object_t *grp_vol_obj)
+H5G__close_cb(H5VL_object_t *grp_vol_obj, void **request)
 {
     herr_t ret_value = SUCCEED; /* Return value */
 
@@ -273,7 +273,7 @@ H5G__close_cb(H5VL_object_t *grp_vol_obj)
     HDassert(grp_vol_obj);
 
     /* Close the group */
-    if (H5VL_group_close(grp_vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
+    if (H5VL_group_close(grp_vol_obj, H5P_DATASET_XFER_DEFAULT, request) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CLOSEERROR, FAIL, "unable to close group")
 
     /* Free the VOL object */
diff --git a/src/H5Iint.c b/src/H5Iint.c
index 95baa28..b511cb5 100644
--- a/src/H5Iint.c
+++ b/src/H5Iint.c
@@ -77,6 +77,9 @@ typedef struct {
 static void * H5I__unwrap(void *object, H5I_type_t type);
 static htri_t H5I__clear_type_cb(void *_id, void *key, void *udata);
 static void * H5I__remove_common(H5I_type_info_t *type_info, hid_t id);
+static int    H5I__dec_ref(hid_t id, void **request);
+static int    H5I__dec_app_ref(hid_t id, void **request);
+static int    H5I__dec_app_ref_always_close(hid_t id, void **request);
 static int    H5I__find_id_cb(void *_item, void *_key, void *_udata);
 
 /*********************/
@@ -367,7 +370,7 @@ H5I__clear_type_cb(void *_info, void H5_ATTR_UNUSED *key, void *_udata)
         /* Check for a 'free' function and call it, if it exists */
         H5_GCC_DIAG_OFF("cast-qual")
         if (udata->type_info->cls->free_func &&
-            (udata->type_info->cls->free_func)((void *)info->object) < 0) { /* (Casting away const OK -QAK) */
+            (udata->type_info->cls->free_func)((void *)info->object, H5_REQUEST_NULL) < 0) { /* (Casting away const OK -QAK) */
             if (udata->force) {
 #ifdef H5I_DEBUG
                 if (H5DEBUG(I)) {
@@ -887,7 +890,7 @@ done:
 } /* end H5I_remove() */
 
 /*-------------------------------------------------------------------------
- * Function:    H5I_dec_ref
+ * Function:    H5I__dec_ref
  *
  * Purpose:     Decrements the number of references outstanding for an ID.
  *              This will fail if the type is not a reference counted type.
@@ -895,18 +898,21 @@ done:
  *              if the reference count for the ID reaches 0 and a free
  *              function has been defined at type creation time.
  *
+ * Note:        Allows for asynchronous 'close' operation on object, with
+ *              request != H5_REQUEST_NULL.
+ *
  * Return:      Success:    New reference count
  *              Failure:    -1
  *
  *-------------------------------------------------------------------------
  */
-int
-H5I_dec_ref(hid_t id)
+static int
+H5I__dec_ref(hid_t id, void **request)
 {
     H5I_id_info_t *info      = NULL; /* Pointer to the ID */
     int            ret_value = 0;    /* Return value */
 
-    FUNC_ENTER_NOAPI((-1))
+    FUNC_ENTER_STATIC
 
     /* Sanity check */
     HDassert(id >= 0);
@@ -937,7 +943,7 @@ H5I_dec_ref(hid_t id)
 
         H5_GCC_DIAG_OFF("cast-qual")
         /* (Casting away const OK -QAK) */
-        if (!type_info->cls->free_func || (type_info->cls->free_func)((void *)info->object) >= 0) {
+        if (!type_info->cls->free_func || (type_info->cls->free_func)((void *)info->object, request) >= 0) {
             /* Remove the node from the type */
             if (NULL == H5I__remove_common(type_info, id))
                 HGOTO_ERROR(H5E_ID, H5E_CANTDELETE, (-1), "can't remove ID node")
@@ -954,34 +960,62 @@ H5I_dec_ref(hid_t id)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5I__dec_ref */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5I_dec_ref
+ *
+ * Purpose:     Decrements the number of references outstanding for an ID.
+ *
+ * Return:      Success:    New reference count
+ *              Failure:    -1
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+H5I_dec_ref(hid_t id)
+{
+    int ret_value = 0; /* Return value */
+
+    FUNC_ENTER_NOAPI((-1))
+
+    /* Sanity check */
+    HDassert(id >= 0);
+
+    /* Synchronously decrement refcount on ID */
+    if ((ret_value = H5I__dec_ref(id, H5_REQUEST_NULL)) < 0)
+        HGOTO_ERROR(H5E_ID, H5E_CANTDEC, (-1), "can't decrement ID ref count")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5I_dec_ref() */
 
 /*-------------------------------------------------------------------------
- * Function:    H5I_dec_app_ref
+ * Function:    H5I__dec_app_ref
  *
  * Purpose:     Wrapper for case of modifying the application ref.
  *              count for an ID as well as normal reference count.
  *
+ * Note:        Allows for asynchronous 'close' operation on object, with
+ *              request != H5_REQUEST_NULL.
+ *
  * Return:      Success:    New app. reference count
  *              Failure:    -1
  *
- * Programmer:  Quincey Koziol
- *              Sept 16, 2010
- *
  *-------------------------------------------------------------------------
  */
-int
-H5I_dec_app_ref(hid_t id)
+static int
+H5I__dec_app_ref(hid_t id, void **request)
 {
     int ret_value = 0; /* Return value */
 
-    FUNC_ENTER_NOAPI((-1))
+    FUNC_ENTER_STATIC
 
     /* Sanity check */
     HDassert(id >= 0);
 
     /* Call regular decrement reference count routine */
-    if ((ret_value = H5I_dec_ref(id)) < 0)
+    if ((ret_value = H5I__dec_ref(id, request)) < 0)
         HGOTO_ERROR(H5E_ID, H5E_CANTDEC, (-1), "can't decrement ID ref count")
 
     /* Check if the ID still exists */
@@ -1002,31 +1036,66 @@ H5I_dec_app_ref(hid_t id)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5I__dec_app_ref() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5I_dec_app_ref
+ *
+ * Purpose:     Wrapper for case of modifying the application ref. count for
+ *              an ID as well as normal reference count.
+ *
+ * Return:      Success:    New app. reference count
+ *              Failure:    -1
+ *
+ * Programmer:  Quincey Koziol
+ *              Sept 16, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+H5I_dec_app_ref(hid_t id)
+{
+    int ret_value = 0; /* Return value */
+
+    FUNC_ENTER_NOAPI((-1))
+
+    /* Sanity check */
+    HDassert(id >= 0);
+
+    /* Synchronously decrement refcount on ID */
+    if ((ret_value = H5I__dec_app_ref(id, H5_REQUEST_NULL)) < 0)
+        HGOTO_ERROR(H5E_ID, H5E_CANTDEC, (-1), "can't decrement ID ref count")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5I_dec_app_ref() */
 
 /*-------------------------------------------------------------------------
- * Function:    H5I_dec_app_ref_always_close
+ * Function:    H5I__dec_app_ref_always_close
  *
  * Purpose:     Wrapper for case of always closing the ID, even when the free
  *              routine fails
  *
+ * Note:        Allows for asynchronous 'close' operation on object, with
+ *              request != H5_REQUEST_NULL.
+ *
  * Return:      Success:    New app. reference count
  *              Failure:    -1
  *
  *-------------------------------------------------------------------------
  */
-int
-H5I_dec_app_ref_always_close(hid_t id)
+static int
+H5I__dec_app_ref_always_close(hid_t id, void **request)
 {
     int ret_value = 0; /* Return value */
 
-    FUNC_ENTER_NOAPI((-1))
+    FUNC_ENTER_STATIC
 
     /* Sanity check */
     HDassert(id >= 0);
 
     /* Call application decrement reference count routine */
-    ret_value = H5I_dec_app_ref(id);
+    ret_value = H5I__dec_app_ref(id, request);
 
     /* Check for failure */
     if (ret_value < 0) {
@@ -1039,7 +1108,36 @@ H5I_dec_app_ref_always_close(hid_t id)
         H5I_remove(id);
 
         HGOTO_ERROR(H5E_ID, H5E_CANTDEC, (-1), "can't decrement ID ref count")
-    }
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5I__dec_app_ref_always_close() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5I_dec_app_ref_always_close
+ *
+ * Purpose:     Wrapper for case of always closing the ID, even when the free
+ *              routine fails.
+ *
+ * Return:      Success:    New app. reference count
+ *              Failure:    -1
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+H5I_dec_app_ref_always_close(hid_t id)
+{
+    int ret_value = 0; /* Return value */
+
+    FUNC_ENTER_NOAPI((-1))
+
+    /* Sanity check */
+    HDassert(id >= 0);
+
+    /* Synchronously decrement refcount on ID */
+    if ((ret_value = H5I__dec_app_ref_always_close(id, H5_REQUEST_NULL)) < 0)
+        HGOTO_ERROR(H5E_ID, H5E_CANTDEC, (-1), "can't decrement ID ref count")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
diff --git a/src/H5Ipublic.h b/src/H5Ipublic.h
index 9c5b5d4..3912252 100644
--- a/src/H5Ipublic.h
+++ b/src/H5Ipublic.h
@@ -80,7 +80,7 @@ typedef int64_t hid_t;
  * can be removed from the ID type. If the function returns negative
  * (failure) then the object will remain in the ID type.
  */
-typedef herr_t (*H5I_free_t)(void *);
+typedef herr_t (*H5I_free_t)(void *, void **);
 
 /**
  * The type of a function to compare objects & keys
diff --git a/src/H5M.c b/src/H5M.c
index 4f9e9cb..4cb5d3a 100644
--- a/src/H5M.c
+++ b/src/H5M.c
@@ -38,7 +38,7 @@
 /********************/
 /* Local Prototypes */
 /********************/
-static herr_t H5M__close_cb(H5VL_object_t *map_vol_obj);
+static herr_t H5M__close_cb(H5VL_object_t *map_vol_obj, void **request);
 
 /*********************/
 /* Package Variables */
@@ -195,7 +195,7 @@ H5M_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5M__close_cb(H5VL_object_t *map_vol_obj)
+H5M__close_cb(H5VL_object_t *map_vol_obj, void **request)
 {
     herr_t ret_value = SUCCEED; /* Return value */
 
@@ -205,7 +205,7 @@ H5M__close_cb(H5VL_object_t *map_vol_obj)
     HDassert(map_vol_obj);
 
     /* Close the map */
-    if (H5VL_optional(map_vol_obj, H5VL_MAP_CLOSE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
+    if (H5VL_optional(map_vol_obj, H5VL_MAP_CLOSE, H5P_DATASET_XFER_DEFAULT, request) < 0)
         HGOTO_ERROR(H5E_MAP, H5E_CLOSEERROR, FAIL, "unable to close map");
 
     /* Free the VOL object */
diff --git a/src/H5Pint.c b/src/H5Pint.c
index df8516d..0d9fad7 100644
--- a/src/H5Pint.c
+++ b/src/H5Pint.c
@@ -95,6 +95,10 @@ typedef herr_t (*H5P_do_pclass_op_t)(H5P_genplist_t *plist, const char *name, H5
 /* Local Prototypes */
 /********************/
 
+/* Infrastructure routines */
+static herr_t H5P__close_class_cb(void *space, void **request);
+static herr_t H5P__close_list_cb(void *space, void **request);
+
 /* General helper routines */
 static H5P_genplist_t *H5P__create(H5P_genclass_t *pclass);
 static H5P_genprop_t * H5P__create_prop(const char *name, size_t size, H5P_prop_within_t type,
@@ -393,18 +397,18 @@ H5FL_DEFINE_STATIC(H5P_genplist_t);
 
 /* Generic Property Class ID class */
 static const H5I_class_t H5I_GENPROPCLS_CLS[1] = {{
-    H5I_GENPROP_CLS,             /* ID class value */
-    0,                           /* Class flags */
-    0,                           /* # of reserved IDs for class */
-    (H5I_free_t)H5P__close_class /* Callback routine for closing objects of this class */
+    H5I_GENPROP_CLS,                /* ID class value */
+    0,                              /* Class flags */
+    0,                              /* # of reserved IDs for class */
+    (H5I_free_t)H5P__close_class_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Generic Property List ID class */
 static const H5I_class_t H5I_GENPROPLST_CLS[1] = {{
-    H5I_GENPROP_LST,      /* ID class value */
-    0,                    /* Class flags */
-    0,                    /* # of reserved IDs for class */
-    (H5I_free_t)H5P_close /* Callback routine for closing objects of this class */
+    H5I_GENPROP_LST,               /* ID class value */
+    0,                             /* Class flags */
+    0,                             /* # of reserved IDs for class */
+    (H5I_free_t)H5P__close_list_cb /* Callback routine for closing objects of this class */
 }};
 
 /*-------------------------------------------------------------------------
@@ -621,6 +625,68 @@ H5P_term_package(void)
     FUNC_LEAVE_NOAPI(n)
 } /* end H5P_term_package() */
 
+/*-------------------------------------------------------------------------
+ * Function:    H5P__close_class_cb
+ *
+ * Purpose:     Called when the ref count reaches zero on a property class's ID
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *	        Wednesday, April 8, 2020
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__close_class_cb(void *_pclass, void H5_ATTR_UNUSED **request)
+{
+    H5P_genclass_t *pclass    = (H5P_genclass_t *)_pclass; /* Property list class to close */
+    herr_t          ret_value = SUCCEED;                   /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity check */
+    HDassert(pclass);
+
+    /* Close the property list class object */
+    if (H5P__close_class(pclass) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CLOSEERROR, FAIL, "unable to close property list class");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__close_class_cb() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P__close_list_cb
+ *
+ * Purpose:     Called when the ref count reaches zero on a property list's ID
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *	        Wednesday, April 8, 2020
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__close_list_cb(void *_plist, void H5_ATTR_UNUSED **request)
+{
+    H5P_genplist_t *plist     = (H5P_genplist_t *)_plist; /* Property list to close */
+    herr_t          ret_value = SUCCEED;                  /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity check */
+    HDassert(plist);
+
+    /* Close the property list object */
+    if (H5P_close(plist) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CLOSEERROR, FAIL, "unable to close property list");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P__close_list_cb() */
+
 /*--------------------------------------------------------------------------
  NAME
     H5P__do_prop_cb1
@@ -5010,10 +5076,9 @@ done:
  REVISION LOG
 --------------------------------------------------------------------------*/
 herr_t
-H5P_close(void *_plist)
+H5P_close(H5P_genplist_t *plist)
 {
     H5P_genclass_t *tclass;              /* Temporary class pointer */
-    H5P_genplist_t *plist = (H5P_genplist_t *)_plist;
     H5SL_t *        seen = NULL;         /* Skip list to hold names of properties already seen */
     size_t          nseen;               /* Number of items 'seen' */
     hbool_t         has_parent_class;    /* Flag to indicate that this property list's class has a parent */
@@ -5393,10 +5458,9 @@ H5P__get_class_parent(const H5P_genclass_t *pclass)
  REVISION LOG
 --------------------------------------------------------------------------*/
 herr_t
-H5P__close_class(void *_pclass)
+H5P__close_class(H5P_genclass_t *pclass)
 {
-    H5P_genclass_t *pclass    = (H5P_genclass_t *)_pclass;
-    herr_t          ret_value = SUCCEED; /* Return value */
+    herr_t ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
diff --git a/src/H5Ppkg.h b/src/H5Ppkg.h
index 075eae0..157e34a 100644
--- a/src/H5Ppkg.h
+++ b/src/H5Ppkg.h
@@ -165,7 +165,7 @@ H5_DLL herr_t H5P__unregister(H5P_genclass_t *pclass, const char *name);
 H5_DLL char * H5P__get_class_path(H5P_genclass_t *pclass);
 H5_DLL H5P_genclass_t *H5P__open_class_path(const char *path);
 H5_DLL H5P_genclass_t *H5P__get_class_parent(const H5P_genclass_t *pclass);
-H5_DLL herr_t          H5P__close_class(void *_pclass);
+H5_DLL herr_t          H5P__close_class(H5P_genclass_t *pclass);
 H5_DLL H5P_genprop_t *H5P__find_prop_plist(const H5P_genplist_t *plist, const char *name);
 H5_DLL hid_t          H5P__new_plist_of_type(H5P_plist_type_t type);
 
diff --git a/src/H5Pprivate.h b/src/H5Pprivate.h
index 926b5ca..ef9ad46 100644
--- a/src/H5Pprivate.h
+++ b/src/H5Pprivate.h
@@ -160,7 +160,7 @@ struct H5VL_connector_prop_t;
 H5_DLL herr_t H5P_init(void);
 
 /* Internal versions of API routines */
-H5_DLL herr_t H5P_close(void *_plist);
+H5_DLL herr_t H5P_close(H5P_genplist_t *plist);
 H5_DLL hid_t  H5P_create_id(H5P_genclass_t *pclass, hbool_t app_ref);
 H5_DLL hid_t  H5P_copy_plist(const H5P_genplist_t *old_plist, hbool_t app_ref);
 H5_DLL herr_t H5P_get(H5P_genplist_t *plist, const char *name, void *value);
diff --git a/src/H5S.c b/src/H5S.c
index a9a0119..a03b58a 100644
--- a/src/H5S.c
+++ b/src/H5S.c
@@ -44,6 +44,7 @@
 /********************/
 /* Local Prototypes */
 /********************/
+static herr_t H5S__close_cb(void *space, void **request);
 static htri_t H5S__is_simple(const H5S_t *sdim);
 
 /*****************************/
@@ -81,18 +82,18 @@ H5FL_ARR_DEFINE(hsize_t, H5S_MAX_RANK);
 
 /* Dataspace ID class */
 static const H5I_class_t H5I_DATASPACE_CLS[1] = {{
-    H5I_DATASPACE,        /* ID class value */
-    0,                    /* Class flags */
-    2,                    /* # of reserved IDs for class */
-    (H5I_free_t)H5S_close /* Callback routine for closing objects of this class */
+    H5I_DATASPACE,            /* ID class value */
+    0,                        /* Class flags */
+    2,                        /* # of reserved IDs for class */
+    (H5I_free_t)H5S__close_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Dataspace selection iterator ID class */
 static const H5I_class_t H5I_SPACE_SEL_ITER_CLS[1] = {{
-    H5I_SPACE_SEL_ITER,            /* ID class value */
-    0,                             /* Class flags */
-    0,                             /* # of reserved IDs for class */
-    (H5I_free_t)H5S_sel_iter_close /* Callback routine for closing objects of this class */
+    H5I_SPACE_SEL_ITER,                /* ID class value */
+    0,                                 /* Class flags */
+    0,                                 /* # of reserved IDs for class */
+    (H5I_free_t)H5S__sel_iter_close_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Flag indicating "top" of interface has been initialized */
@@ -222,6 +223,37 @@ H5S_term_package(void)
     FUNC_LEAVE_NOAPI(n)
 } /* end H5S_term_package() */
 
+/*-------------------------------------------------------------------------
+ * Function:    H5S__close_cb
+ *
+ * Purpose:     Called when the ref count reaches zero on a dataspace's ID
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *	        Wednesday, April 8, 2020
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5S__close_cb(void *_space, void H5_ATTR_UNUSED **request)
+{
+    H5S_t *space     = (H5S_t *)_space; /* The dataspace to close */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity check */
+    HDassert(space);
+
+    /* Close the dataspace object */
+    if (H5S_close(space) < 0)
+        HGOTO_ERROR(H5E_DATASPACE, H5E_CLOSEERROR, FAIL, "unable to close dataspace");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5S__close_cb() */
+
 /*--------------------------------------------------------------------------
  NAME
     H5S_get_validiated_dataspace
diff --git a/src/H5Spkg.h b/src/H5Spkg.h
index adb528e..b744a6a 100644
--- a/src/H5Spkg.h
+++ b/src/H5Spkg.h
@@ -392,6 +392,9 @@ H5_DLL herr_t   H5S__hyper_project_intersection(const H5S_t *src_space, const H5
                                                 const H5S_t *src_intersect_space, H5S_t *proj_space,
                                                 hbool_t share_space);
 
+/* Operations on selection iterators */
+H5_DLL herr_t H5S__sel_iter_close_cb(H5S_sel_iter_t *_sel_iter, void **request);
+
 /* Testing functions */
 #ifdef H5S_TESTING
 H5_DLL herr_t H5S__get_rebuild_status_test(hid_t space_id, H5S_diminfo_valid_t *status1,
diff --git a/src/H5Sselect.c b/src/H5Sselect.c
index f1a6fc1..b3f63b0 100644
--- a/src/H5Sselect.c
+++ b/src/H5Sselect.c
@@ -3140,6 +3140,37 @@ done:
 } /* end H5Ssel_iter_reset() */
 
 /*-------------------------------------------------------------------------
+ * Function:	H5S__sel_iter_close_cb
+ *
+ * Purpose:     Called when the ref count reaches zero on a selection iterator's ID
+ *
+ * Return:	Non-negative on success / Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *	        Wednesday, April 8, 2020
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5S__sel_iter_close_cb(H5S_sel_iter_t *_sel_iter, void H5_ATTR_UNUSED **request)
+{
+    H5S_sel_iter_t *sel_iter  = (H5S_sel_iter_t *)_sel_iter; /* The selection iterator to close */
+    herr_t          ret_value = SUCCEED;                     /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Sanity check */
+    HDassert(sel_iter);
+
+    /* Close the selection iterator object */
+    if (H5S_sel_iter_close(sel_iter) < 0)
+        HGOTO_ERROR(H5E_DATASPACE, H5E_CLOSEERROR, FAIL, "unable to close selection iterator");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5S__sel_iter_close_cb() */
+
+/*-------------------------------------------------------------------------
  * Function:	H5S_sel_iter_close
  *
  * Purpose:	Releases a dataspace selection iterator and its memory.
diff --git a/src/H5T.c b/src/H5T.c
index 2528760..7a81542 100644
--- a/src/H5T.c
+++ b/src/H5T.c
@@ -346,7 +346,7 @@ static herr_t H5T__register(H5T_pers_t pers, const char *name, H5T_t *src, H5T_t
 static herr_t H5T__unregister(H5T_pers_t pers, const char *name, H5T_t *src, H5T_t *dst, H5T_conv_t func);
 static htri_t H5T__compiler_conv(H5T_t *src, H5T_t *dst);
 static herr_t H5T__set_size(H5T_t *dt, size_t size);
-static herr_t H5T__close_cb(H5T_t *dt);
+static herr_t H5T__close_cb(H5T_t *dt, void **request);
 static H5T_path_t *H5T__path_find_real(const H5T_t *src, const H5T_t *dst, const char *name,
                                        H5T_conv_func_t *conv);
 static hbool_t     H5T__detect_vlen_ref(const H5T_t *dt);
@@ -1775,7 +1775,7 @@ H5T_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T__close_cb(H5T_t *dt)
+H5T__close_cb(H5T_t *dt, void **request)
 {
     herr_t ret_value = SUCCEED; /* Return value */
 
@@ -1790,7 +1790,7 @@ H5T__close_cb(H5T_t *dt)
      */
     if (NULL != dt->vol_obj) {
         /* Close the connector-managed datatype data */
-        if (H5VL_datatype_close(dt->vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
+        if (H5VL_datatype_close(dt->vol_obj, H5P_DATASET_XFER_DEFAULT, request) < 0)
             HGOTO_ERROR(H5E_DATATYPE, H5E_CLOSEERROR, FAIL, "unable to close datatype")
 
         /* Free the VOL object */
diff --git a/src/H5VLint.c b/src/H5VLint.c
index b92c16a..10df59a 100644
--- a/src/H5VLint.c
+++ b/src/H5VLint.c
@@ -86,7 +86,7 @@ typedef struct {
 /********************/
 /* Local Prototypes */
 /********************/
-static herr_t         H5VL__free_cls(H5VL_class_t *cls);
+static herr_t         H5VL__free_cls(H5VL_class_t *cls, void **request);
 static int            H5VL__get_connector_cb(void *obj, hid_t id, void *_op_data);
 static herr_t         H5VL__set_def_conn(void);
 static void *         H5VL__wrap_obj(void *obj, H5I_type_t obj_type);
@@ -289,7 +289,7 @@ H5VL_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5VL__free_cls(H5VL_class_t *cls)
+H5VL__free_cls(H5VL_class_t *cls, void H5_ATTR_UNUSED **request)
 {
     herr_t ret_value = SUCCEED;