Am 29.06.2024 um 16:25 hat Michael Tokarev geschrieben:
> Existing code was long, unclear and twisty.
>
> Signed-off-by: Michael Tokarev <m...@tls.msk.ru>
> ---
> block/curl.c | 44 ++++++++++++++++++--------------------------
> 1 file changed, 18 insertions(+), 26 deletions(-)
>
> diff --git a/block/curl.c b/block/curl.c
> index 419f7c89ef..9802d0319d 100644
> --- a/block/curl.c
> +++ b/block/curl.c
> @@ -210,37 +210,29 @@ static size_t curl_header_cb(void *ptr, size_t size,
> size_t nmemb, void *opaque)
> {
> BDRVCURLState *s = opaque;
> size_t realsize = size * nmemb;
> - const char *header = (char *)ptr;
> - const char *end = header + realsize;
> - const char *accept_ranges = "accept-ranges:";
> - const char *bytes = "bytes";
> + const char *p = ptr;
> + const char *end = p + realsize;
> + const char *t = "accept-ranges : bytes "; /* A lowercase template */
I don't think spaces between the field name and the colon are allowed
in the spec (and in the old code), only before and after the value.
> - if (realsize >= strlen(accept_ranges)
> - && g_ascii_strncasecmp(header, accept_ranges,
> - strlen(accept_ranges)) == 0) {
> -
> - char *p = strchr(header, ':') + 1;
> -
> - /* Skip whitespace between the header name and value. */
> - while (p < end && *p && g_ascii_isspace(*p)) {
> - p++;
> - }
> -
> - if (end - p >= strlen(bytes)
> - && strncmp(p, bytes, strlen(bytes)) == 0) {
> -
> - /* Check that there is nothing but whitespace after the value. */
> - p += strlen(bytes);
> - while (p < end && *p && g_ascii_isspace(*p)) {
> - p++;
> - }
> -
> - if (p == end || !*p) {
> - s->accept_range = true;
> + /* check if header matches the "t" template */
> + for (;;) {
> + if (*t == ' ') { /* space in t matches any amount of isspace in p */
> + if (p < end && g_ascii_isspace(*p)) {
> + ++p;
> + } else {
> + ++t;
> }
> + } else if (*t && p < end && *t == g_ascii_tolower(*p)) {
> + ++p, ++t;
> + } else {
> + break;
> }
> }
>
> + if (!*t && p == end) { /* if we managed to reach ends of both strings */
> + s->accept_range = true;
> + }
Maybe make the generic comparison with a template a separate function
(maybe even in cutils.c?) so that curl_header_cb() essentially only has
something like this any more:
if (!qemu_memcasecmp_space(ptr, end, "accept-ranges: bytes ")) {
s->accept_range = true;
}
(A better name for the function would be preferable, of course. Maybe
also a bool return value, but if it has a name related to memcmp() or
strcmp(), then 0 must mean it matches.)
Then this would really highlight the curl specific logic rather than the
string parser in curl_header_cb().
Kevin
