Refactor all the 'H5VL_*_optional' callbacks to move the type of operation out

of the va_list, so it's at least possible for another connector to know what
the operation is and decide whether to implement it or not.

Added a new VOL sub-class called "introspect" where callbacks that report
information about the connector or container can be placed.  Added an
'opt_query' callback to this sub-class, for a connector to report back
to the library whether a particular optional callback operation is supported.
Also added a 'get_conn_cls' introspection callback, to retrieve the H5VL_class_t
of a connector (either the "current" connector, H5VL_GET_CONN_LVL_CURR, or
the terminal connector, H5VL_GET_CONN_LVL_TERM).

Moved the "post open" operation from a file 'specific' operation to a file
'optional' operation, now that it's possible to detect (with the 'opt_query'
introspection callback) whether a VOL connector implements an optional
operation, without just returning an error.

Added new internal VOL helper routines: H5VL_object_is_native, to determine
if an object is in (or is a) native file, and H5VL_file_is_same, to determine
if two objects are in (or are) the same terminal VOL connector's container.
(And moved the special handling for FILE_IS_EQUAL operation out of internal VOL
callback routine into H5VL_file_is_same)

Made new dataset 'get' operation for H5Dvlen_get_buf_size, aligning it better
with other 'get' operations in API.

Fixed several issues with pass-through connectors, which are now passing the
'make check-passthrough-vol' tests again.

A bunch of warning and style cleanups as well.

1 files changed, 33 insertions, 9 deletions

diff --git a/src/H5Rdeprec.c b/src/H5Rdeprec.c
index ad3c219..67a1c26 100644
--- a/src/H5Rdeprec.c
+++ b/src/H5Rdeprec.c
@@ -251,6 +251,19 @@ H5Rcreate(void *ref, hid_t loc_id, const char *name, H5R_type_t ref_type,
     if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
+#ifndef NDEBUG
+{
+    hbool_t is_native = FALSE;  /* Whether the src file is using the native VOL connector */
+
+    /* Check if using native VOL connector */
+    if(H5VL_object_is_native(vol_obj, &is_native) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "can't query if file uses native VOL connector")
+
+    /* Must use native VOL connector for this operation */
+    HDassert(is_native);
+}
+#endif /* NDEBUG */
+
     /* Get object type */
     if((vol_obj_type = H5I_get_type(loc_id)) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
@@ -274,7 +287,7 @@ H5Rcreate(void *ref, hid_t loc_id, const char *name, H5R_type_t ref_type,
         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)
+    if(H5VL_file_get((const H5VL_object_t *)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")
 
     /* Create reference */
@@ -283,7 +296,8 @@ H5Rcreate(void *ref, hid_t loc_id, const char *name, H5R_type_t ref_type,
 
         if((ret_value = H5R__encode_token_obj_compat((const H5VL_token_t *)&obj_token, cont_info.token_size, buf, &buf_size)) < 0)
             HGOTO_ERROR(H5E_REFERENCE, H5E_CANTENCODE, FAIL, "unable to encode object reference")
-    } else {
+    } /* end if */
+    else {
         H5F_t *f = NULL;
         H5S_t *space = NULL; /* Pointer to dataspace containing region */
         size_t buf_size = H5R_DSET_REG_REF_BUF_SIZE;
@@ -294,17 +308,14 @@ H5Rcreate(void *ref, hid_t loc_id, const char *name, H5R_type_t ref_type,
         if(NULL == (space = (struct H5S_t *)H5I_object_verify(space_id, H5I_DATASPACE)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a dataspace")
 
-        /* Currently restrict API usage to native VOL
-         * TODO check for terminal connector or use capability flag */
-
         /* Retrieve file from VOL object */
-        if(NULL == (f = (H5F_t *)H5VL_object_data(vol_obj_file)))
+        if(NULL == (f = (H5F_t *)H5VL_object_data((const H5VL_object_t *)vol_obj_file)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid VOL object")
 
         /* Encode dataset region */
         if((ret_value = H5R__encode_token_region_compat(f, (const H5VL_token_t *)&obj_token, cont_info.token_size, space, buf, &buf_size)) < 0)
             HGOTO_ERROR(H5E_REFERENCE, H5E_CANTENCODE, FAIL, "unable to encode region reference")
-    }
+    } /* end else */
 
 done:
     if(file_id != H5I_INVALID_HID && H5I_dec_ref(file_id) < 0)
@@ -475,6 +486,19 @@ H5Rget_region(hid_t id, H5R_type_t ref_type, const void *ref)
     if(NULL == (vol_obj = H5VL_vol_object(id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid file identifier")
 
+#ifndef NDEBUG
+{
+    hbool_t is_native = FALSE;  /* Whether the src file is using the native VOL connector */
+
+    /* Check if using native VOL connector */
+    if(H5VL_object_is_native(vol_obj, &is_native) < 0)
+        HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "can't query if file uses native VOL connector")
+
+    /* Must use native VOL connector for this operation */
+    HDassert(is_native);
+}
+#endif /* NDEBUG */
+
     /* Get object type */
     if((vol_obj_type = H5I_get_type(id)) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
@@ -488,11 +512,11 @@ H5Rget_region(hid_t id, H5R_type_t ref_type, const void *ref)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "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)
+    if(H5VL_file_get((const H5VL_object_t *)vol_obj_file, H5VL_FILE_GET_CONT_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &cont_info) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, H5I_INVALID_HID, "unable to get container info")
 
     /* Retrieve file from VOL object */
-    if(NULL == (f = (H5F_t *)H5VL_object_data(vol_obj_file)))
+    if(NULL == (f = (H5F_t *)H5VL_object_data((const H5VL_object_t *)vol_obj_file)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid VOL object")
 
     /* Get the dataspace with the correct region selected */