in modules/mappers/mod_negotiation.c [2433:2610]
static void set_neg_headers(request_rec *r, negotiation_state *neg,
int alg_result)
{
apr_table_t *hdrs;
var_rec *avail_recs = (var_rec *) neg->avail_vars->elts;
const char *sample_type = NULL;
const char *sample_language = NULL;
const char *sample_encoding = NULL;
const char *sample_charset = NULL;
char *lang;
char *qstr;
apr_off_t len;
apr_array_header_t *arr;
int max_vlist_array = (neg->avail_vars->nelts * 21);
int first_variant = 1;
int vary_by_type = 0;
int vary_by_language = 0;
int vary_by_charset = 0;
int vary_by_encoding = 0;
int j;
/* In order to avoid O(n^2) memory copies in building Alternates,
* we preallocate a apr_table_t with the maximum substrings possible,
* fill it with the variant list, and then concatenate the entire array.
* Note that if you change the number of substrings pushed, you also
* need to change the calculation of max_vlist_array above.
*/
if (neg->send_alternates && neg->avail_vars->nelts)
arr = apr_array_make(r->pool, max_vlist_array, sizeof(char *));
else
arr = NULL;
/* Put headers into err_headers_out, since send_http_header()
* outputs both headers_out and err_headers_out.
*/
hdrs = r->err_headers_out;
for (j = 0; j < neg->avail_vars->nelts; ++j) {
var_rec *variant = &avail_recs[j];
if (variant->content_languages && variant->content_languages->nelts) {
lang = apr_array_pstrcat(r->pool, variant->content_languages, ',');
}
else {
lang = NULL;
}
/* Calculate Vary by looking for any difference between variants */
if (first_variant) {
sample_type = variant->mime_type;
sample_charset = variant->content_charset;
sample_language = lang;
sample_encoding = variant->content_encoding;
}
else {
if (!vary_by_type &&
strcmp(sample_type ? sample_type : "",
variant->mime_type ? variant->mime_type : "")) {
vary_by_type = 1;
}
if (!vary_by_charset &&
strcmp(sample_charset ? sample_charset : "",
variant->content_charset ?
variant->content_charset : "")) {
vary_by_charset = 1;
}
if (!vary_by_language &&
strcmp(sample_language ? sample_language : "",
lang ? lang : "")) {
vary_by_language = 1;
}
if (!vary_by_encoding &&
strcmp(sample_encoding ? sample_encoding : "",
variant->content_encoding ?
variant->content_encoding : "")) {
vary_by_encoding = 1;
}
}
first_variant = 0;
if (!neg->send_alternates)
continue;
/* Generate the string components for this Alternates entry */
*((const char **) apr_array_push(arr)) = "{\"";
*((const char **) apr_array_push(arr)) = ap_escape_path_segment(r->pool, variant->file_name);
*((const char **) apr_array_push(arr)) = "\" ";
qstr = (char *) apr_palloc(r->pool, 6);
apr_snprintf(qstr, 6, "%1.3f", variant->source_quality);
/* Strip trailing zeros (saves those valuable network bytes) */
if (qstr[4] == '0') {
qstr[4] = '\0';
if (qstr[3] == '0') {
qstr[3] = '\0';
if (qstr[2] == '0') {
qstr[1] = '\0';
}
}
}
*((const char **) apr_array_push(arr)) = qstr;
if (variant->mime_type && *variant->mime_type) {
*((const char **) apr_array_push(arr)) = " {type ";
*((const char **) apr_array_push(arr)) = variant->mime_type;
*((const char **) apr_array_push(arr)) = "}";
}
if (variant->content_charset && *variant->content_charset) {
*((const char **) apr_array_push(arr)) = " {charset ";
*((const char **) apr_array_push(arr)) = variant->content_charset;
*((const char **) apr_array_push(arr)) = "}";
}
if (lang) {
*((const char **) apr_array_push(arr)) = " {language ";
*((const char **) apr_array_push(arr)) = lang;
*((const char **) apr_array_push(arr)) = "}";
}
if (variant->content_encoding && *variant->content_encoding) {
/* Strictly speaking, this is non-standard, but so is TCN */
*((const char **) apr_array_push(arr)) = " {encoding ";
*((const char **) apr_array_push(arr)) = variant->content_encoding;
*((const char **) apr_array_push(arr)) = "}";
}
/* Note that the Alternates specification (in rfc2295) does
* not require that we include {length x}, so we could omit it
* if determining the length is too expensive. We currently
* always include it though.
*
* If the variant is a CGI script, find_content_length would
* return the length of the script, not the output it
* produces, so we check for the presence of a handler and if
* there is one we don't add a length.
*
* XXX: TODO: This check does not detect a CGI script if we
* get the variant from a type map. This needs to be fixed
* (without breaking things if the type map specifies a
* content-length, which currently leads to the correct result).
*/
if (!(variant->sub_req && variant->sub_req->handler)
&& (len = find_content_length(neg, variant)) >= 0) {
*((const char **) apr_array_push(arr)) = " {length ";
*((const char **) apr_array_push(arr)) = apr_off_t_toa(r->pool,
len);
*((const char **) apr_array_push(arr)) = "}";
}
*((const char **) apr_array_push(arr)) = "}";
*((const char **) apr_array_push(arr)) = ", "; /* trimmed below */
}
if (neg->send_alternates && neg->avail_vars->nelts) {
arr->nelts--; /* remove last comma */
apr_table_mergen(hdrs, "Alternates",
apr_array_pstrcat(r->pool, arr, '\0'));
}
if (neg->is_transparent || vary_by_type || vary_by_language ||
vary_by_charset || vary_by_encoding) {
apr_table_mergen(hdrs, "Vary", 2 + apr_pstrcat(r->pool,
neg->is_transparent ? ", negotiate" : "",
vary_by_type ? ", accept" : "",
vary_by_language ? ", accept-language" : "",
vary_by_charset ? ", accept-charset" : "",
vary_by_encoding ? ", accept-encoding" : "", NULL));
}
if (neg->is_transparent) { /* Create TCN response header */
apr_table_setn(hdrs, "TCN",
alg_result == alg_list ? "list" : "choice");
}
}