Re: [Libguestfs] [nbdkit PATCH v3 12/16] filters: New API for plugin context management

As promised in an earlier patch, get rid of the temporary nbdkit_backend_reopen, and replace it with the finer-grained combination of nbdkit_context_get_backend, nbdkit_context_next_open, nbdkit_context_next_close, and nbdkit_context_set_next. Update the

retry filter to use the new API. Change the (temporary) preprocessor guard from NBDKIT_RETRY_FILTER to NBDKIT_TYPESAFE (will be dropped later once more filters are converted). Drop the now-unused backend_reopen() function. Expose .prepare and .finalize callbacks into struct nbdkit_next_ops for use during manual context manipulation. With this in place, it is now possible for a filter to open more than one context into the backend from a single connection (shown here in the retry filter), and conversely to share a single backend context across multiple connections (an upcoming patch will demonstrate this in the ext2 filter, although TODO mentions a few more steps we need to get there). ---

+ +=head3 C<nbdkit_context_get_backend> + +=head3 C<nbdkit_next_context_open> + +=head3 C<nbdkit_next_context_close> + +=head3 C<nbdkit_context_set_next> +