[PATCH 06 of 20] Reworked multi headers to use linked lists

[Sergey Kandaurov]

> On 21 Apr 2022, at 02:18, Maxim Dounin <mdounin at mdounin.ru> wrote:
> 
> # HG changeset patch
> # User Maxim Dounin <mdounin at mdounin.ru>
> # Date 1650492323 -10800
> #      Thu Apr 21 01:05:23 2022 +0300
> # Node ID 50fe52f516ff9c148aa9e7dfcc1c31cc6a4929ae
> # Parent  2ea48b5e4643a818cd81179f040f0b36be9050d6
> Reworked multi headers to use linked lists.
> 
> Multi headers are now using linked lists instead of arrays.  Notably,
> the following fields were changed: r->headers_in.cookies (renamed
> to r->headers_in.cookie), r->headers_in.x_forwarded_for,
> r->headers_out.cache_control, r->headers_out.link, u->headers_in.cache_control
> u->headers_in.cookies (renamed to u->headers_in.set_cookie).
> 
> The r->headers_in.cookies and u->headers_in.cookies fields were renamed
> to r->headers_in.cookie and u->headers_in.set_cookie to match header names.
> 
> The ngx_http_parse_multi_header_lines() and ngx_http_parse_set_cookie_lines()
> functions were changed accordingly.
> 
> With this change, multi headers are now essentially equivalent to normal
> headers, and following changes will further make them equivalent.
> 
> [...]
> 
> diff --git a/src/http/modules/perl/nginx.xs b/src/http/modules/perl/nginx.xs
> --- a/src/http/modules/perl/nginx.xs
> +++ b/src/http/modules/perl/nginx.xs
> @@ -302,7 +302,7 @@ header_in(r, key)
> 
>     if (hh) {
> 
> -        if (hh->offset == offsetof(ngx_http_headers_in_t, cookies)) {
> +        if (hh->offset == offsetof(ngx_http_headers_in_t, cookie)) {
>             sep = ';';
>             goto multi;
>         }
> @@ -327,17 +327,13 @@ header_in(r, key)
> 
>         /* Cookie, X-Forwarded-For */
> 
> -        a = (ngx_array_t *) ((char *) &r->headers_in + hh->offset);
> +        ph = (ngx_table_elt_t **) ((char *) &r->headers_in + hh->offset);
> 
> -        n = a->nelts;
> -
> -        if (n == 0) {
> +        if (*ph == NULL) {
>             XSRETURN_UNDEF;
>         }
> 
> -        ph = a->elts;
> -
> -        if (n == 1) {
> +        if ((*ph)->next == NULL) {
>             ngx_http_perl_set_targ((*ph)->value.data, (*ph)->value.len);
> 
>             goto done;
> @@ -345,8 +341,8 @@ header_in(r, key)
> 
>         size = - (ssize_t) (sizeof("; ") - 1);
> 
> -        for (i = 0; i < n; i++) {
> -            size += ph[i]->value.len + sizeof("; ") - 1;
> +        for (h = *ph; h; h = h->next) {
> +            size += h->value.len + sizeof("; ") - 1;
>         }
> 
>         value = ngx_pnalloc(r->pool, size);
> @@ -357,10 +353,10 @@ header_in(r, key)
> 
>         p = value;
> 
> -        for (i = 0; /* void */ ; i++) {
> -            p = ngx_copy(p, ph[i]->value.data, ph[i]->value.len);
> +        for (h = *ph; h; h = h->next) {
> +            p = ngx_copy(p, h->value.data, h->value.len);
> 
> -            if (i == n - 1) {
> +            if (h->next == NULL) {
>                 break;
>             }
> [...]

A follow-up I would like to commit.
It is caught on distributions that have -Wall in Perl's config_args:
nginx.xs:273:33: warning: unused variable ‘a’ [-Wunused-variable]
nginx.xs:272:36: warning: unused variable ‘n’ [-Wunused-variable]

# HG changeset patch
# User Sergey Kandaurov <pluknet at nginx.com>
# Date 1655137187 -14400
#      Mon Jun 13 20:19:47 2022 +0400
# Node ID f1d335894234ea518f4b6d7064fc3aeba89706cc
# Parent  aa28c802409fb7a74e3323195f859d09fe73cd6d
Perl: removed unused variables, forgotten in ef6a3a99a81a.

diff --git a/src/http/modules/perl/nginx.xs b/src/http/modules/perl/nginx.xs
--- a/src/http/modules/perl/nginx.xs
+++ b/src/http/modules/perl/nginx.xs
@@ -269,8 +269,7 @@ header_in(r, key)
     u_char                     *p, *lowcase_key, *value, sep;
     STRLEN                      len;
     ssize_t                     size;
-    ngx_uint_t                  i, n, hash;
-    ngx_array_t                *a;
+    ngx_uint_t                  i, hash;
     ngx_list_part_t            *part;
     ngx_table_elt_t            *h, *header, **ph;
     ngx_http_header_t          *hh;

-- 
Sergey Kandaurov