Re: [PATCH v2 1/4] Add cleaner line-by-line reading primitives

[Stefano Brivio <sbrivio@redhat.com>]

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On Fri, 24 Jun 2022 12:17:29 +1000
David Gibson <david(a)gibson.dropbear.id.au> wrote:

> [...]
>
> +/**
> + * lineread_get() - Read a single line from file (no allocation)
> + * @lr:		Line reader state structure
> + * @line:	Place a pointer to the next line in this variable
> + *
> + * Return:	Length of line read on success, 0 on EOF, negative on error
> + */
> +int lineread_get(struct lineread *lr, char **line)
> +{
> +	bool eof = false;
> +	int line_len;
> +
> +	while ((line_len = peek_line(lr, eof)) < 0) {
> +		int rc;
> +
> +		if ((lr->next_line + lr->count) == LINEREAD_BUFFER_SIZE) {
> +			/* No space at end */
> +			if (lr->next_line == 0) {
> +				/* Buffer is full, which means we've
> +				 * hit a line too long for us to
> +				 * process.  FIXME: report error
> +				 * better
> +				 */
> +				return -1;
> +			}
> +			memmove(lr->buf, lr->buf + lr->next_line, lr->count);
> +			lr->next_line = 0;
> +		}
> +
> +		/* Read more data into the end of buffer */
> +		rc = read(lr->fd, lr->buf + lr->next_line + lr->count,
> +			  LINEREAD_BUFFER_SIZE - lr->next_line - lr->count);
> +		if (rc < 0) {
> +			return rc;
> +		} else if (rc == 0) {

clang-tidy still complains about this one, and I think it's reasonable
(though not fundamental) to change it, because (rc < 0) is a clear
error condition we're returning right away. I'd just change this on
merge.

-- 
Stefano