Allow read-only VFD registration (#257)

* Removes no-op callback stubs from read-only VFDs

Also changes VFD registration to allow read-only VFDs with no
write callback to be registered.

* Adds a RELEASE.txt note for HDFFV-11205

For the read-only VFD registration change

1 files changed, 4 insertions, 138 deletions

diff --git a/src/H5FDhdfs.c b/src/H5FDhdfs.c
index 43ad9a1..1b28168 100644
--- a/src/H5FDhdfs.c
+++ b/src/H5FDhdfs.c
@@ -271,12 +271,6 @@ static haddr_t H5FD__hdfs_get_eof(const H5FD_t *_file, H5FD_mem_t type);
 static herr_t  H5FD__hdfs_get_handle(H5FD_t *_file, hid_t fapl, void **file_handle);
 static herr_t  H5FD__hdfs_read(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr, size_t size,
                                void *buf);
-static herr_t  H5FD__hdfs_write(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr, size_t size,
-                                const void *buf);
-static herr_t  H5FD__hdfs_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing);
-static herr_t  H5FD__hdfs_lock(H5FD_t *_file, hbool_t rw);
-static herr_t  H5FD__hdfs_unlock(H5FD_t *_file);
-
 static herr_t H5FD__hdfs_validate_config(const H5FD_hdfs_fapl_t *fa);
 
 static const H5FD_class_t H5FD_hdfs_g = {
@@ -306,11 +300,11 @@ static const H5FD_class_t H5FD_hdfs_g = {
     H5FD__hdfs_get_eof,       /* get_eof              */
     H5FD__hdfs_get_handle,    /* get_handle           */
     H5FD__hdfs_read,          /* read                 */
-    H5FD__hdfs_write,         /* write                */
+    NULL,                     /* write                */
     NULL,                     /* flush                */
-    H5FD__hdfs_truncate,      /* truncate             */
-    H5FD__hdfs_lock,          /* lock                 */
-    H5FD__hdfs_unlock,        /* unlock               */
+    NULL,                     /* truncate             */
+    NULL,                     /* lock                 */
+    NULL,                     /* unlock               */
     H5FD_FLMAP_DICHOTOMY      /* fl_map               */
 };
 
@@ -1571,132 +1565,4 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5FD__hdfs_read() */
 
-/*-------------------------------------------------------------------------
- *
- * Function: H5FD__hdfs_write()
- *
- * Purpose:
- *
- *     Write bytes to file.
- *     UNSUPPORTED IN READ-ONLY HDFS VFD.
- *
- * Return:
- *
- *     FAIL (Not possible with Read-Only S3 file.)
- *
- * Programmer: Jacob Smith
- *             2017-10-23
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5FD__hdfs_write(H5FD_t H5_ATTR_UNUSED *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNUSED dxpl_id,
-                 haddr_t H5_ATTR_UNUSED addr, size_t H5_ATTR_UNUSED size, const void H5_ATTR_UNUSED *buf)
-{
-    herr_t ret_value = FAIL;
-
-    FUNC_ENTER_STATIC
-
-#if HDFS_DEBUG
-    HDfprintf(stdout, "called %s.\n", FUNC);
-#endif
-
-    HGOTO_ERROR(H5E_VFL, H5E_UNSUPPORTED, FAIL, "cannot write to read-only file")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5FD__hdfs_write() */
-
-/*-------------------------------------------------------------------------
- *
- * Function: H5FD__hdfs_truncate()
- *
- * Purpose:
- *
- *     Makes sure that the true file size is the same (or larger)
- *     than the end-of-address.
- *
- *     NOT POSSIBLE ON READ-ONLY S3 FILES.
- *
- * Return:
- *
- *     FAIL (Not possible on Read-Only S3 files.)
- *
- * Programmer: Jacob Smith
- *             2017-10-23
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5FD__hdfs_truncate(H5FD_t H5_ATTR_UNUSED *_file, hid_t H5_ATTR_UNUSED dxpl_id,
-                    hbool_t H5_ATTR_UNUSED closing)
-{
-    herr_t ret_value = SUCCEED;
-
-    FUNC_ENTER_STATIC
-
-#if HDFS_DEBUG
-    HDfprintf(stdout, "called %s.\n", FUNC);
-#endif
-
-    HGOTO_ERROR(H5E_VFL, H5E_UNSUPPORTED, FAIL, "cannot truncate read-only file")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FD__hdfs_truncate() */
-
-/*-------------------------------------------------------------------------
- *
- * Function: H5FD__hdfs_lock()
- *
- * Purpose:
- *
- *     Place an advisory lock on a file.
- *     No effect on Read-Only S3 file.
- *
- *     Suggestion: remove lock/unlock from class
- *                 would result in error at H5FD_[un]lock() (H5FD.c)
- *
- * Return:
- *
- *     SUCCEED (No-op always succeeds)
- *
- * Programmer: Jacob Smith
- *             2017-11-03
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5FD__hdfs_lock(H5FD_t H5_ATTR_UNUSED *_file, hbool_t H5_ATTR_UNUSED rw)
-{
-    FUNC_ENTER_STATIC_NOERR
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5FD__hdfs_lock() */
-
-/*-------------------------------------------------------------------------
- *
- * Function: H5FD__hdfs_unlock()
- *
- * Purpose:
- *
- *     Remove the existing lock on the file.
- *     No effect on Read-Only S3 file.
- *
- * Return:
- *
- *     SUCCEED (No-op always succeeds)
- *
- * Programmer: Jacob Smith
- *             2017-11-03
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5FD__hdfs_unlock(H5FD_t H5_ATTR_UNUSED *_file)
-{
-    FUNC_ENTER_STATIC_NOERR
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5FD__hdfs_unlock() */
 #endif /* H5_HAVE_LIBHDFS */