Re: [PATCH v4 4/4] convert: add "status=delayed" to filter process protocol

["Torsten Bögershausen" <tboegi@web.de>]

On 2017-05-22 15:50, Lars Schneider wrote:
> +
> +int async_query_available_blobs(const char *cmd, struct string_list *delayed_paths)
> +{
> +	int err;
> +	char *line;
> +	struct cmd2process *entry;
> +	struct child_process *process;
> +	struct strbuf filter_status = STRBUF_INIT;
> +
> +	entry = find_multi_file_filter_entry(&cmd_process_map, cmd);
> +	if (!entry) {
> +		error("external filter '%s' is not available anymore although "
> +		      "not all paths have been filtered", cmd);
> +		return 0;
> +	}
> +	process = &entry->process;
> +	sigchain_push(SIGPIPE, SIG_IGN);
> +
> +	err = packet_write_fmt_gently(
> +		process->in, "command=list_available_blobs\n");
> +	if (err)
> +		goto done;
> +
> +	err = packet_flush_gently(process->in);
> +	if (err)
> +		goto done;
> +
> +	for (;;) {
> +		const char* pre = "pathname=";
> +		const int pre_len = strlen(pre);
> +		line = packet_read_line(process->out, NULL);
> +		if (!line)
> +			break;
> +		err = strlen(line) <= pre_len || strncmp(line, pre, pre_len);
> +		if (err)
> +			goto done;
> +		string_list_insert(delayed_paths, xstrdup(line+pre_len));
> +	}
> +
> +	read_multi_file_filter_status(process->out, &filter_status);
> +	err = strcmp(filter_status.buf, "success");
> +
> +done:
> +	sigchain_pop(SIGPIPE);
> +
> +	if (err || errno == EPIPE) {

This looks strange, at first glance.
Do we set errno to 0 before ?
Or is there a trick that EPIPE can only be reached,
if it is "our" error ?


> +		if (!strcmp(filter_status.buf, "error")) {
> +			/* The filter signaled a problem with the file. */
> +		} else {
> +			/*
> +			 * Something went wrong with the protocol filter.
> +			 * Force shutdown and restart if another blob requires
> +			 * filtering.
> +			 */
> +			error("external filter '%s' failed", cmd);
> +			kill_multi_file_filter(&cmd_process_map, entry);
> +		}
> +	}
> +	return !err;
> +}
> +