mod_negotiation.c

                    break;
                }
                mime_info.bytes = number;
                has_content = 1;
            }
            else if (!strncmp(buffer, "content-language:", 17)) {
                mime_info.content_languages = do_languages_line(neg->pool,
                                                                &body);
                has_content = 1;
            }
            else if (!strncmp(buffer, "content-encoding:", 17)) {
                mime_info.content_encoding = ap_get_token(neg->pool, &body, 0);
                has_content = 1;
            }
            else if (!strncmp(buffer, "description:", 12)) {
                char *desc = apr_pstrdup(neg->pool, body);
                char *cp;

                for (cp = desc; *cp; ++cp) {
                    if (*cp=='\n') *cp=' ';
                }
                if (cp>desc) *(cp-1)=0;
                mime_info.description = desc;
            }
            else if (!strncmp(buffer, "body:", 5)) {
                char *tag = apr_pstrdup(neg->pool, body);
                char *eol = strchr(tag, '\0');
                apr_size_t len = MAX_STRING_LEN;
                while (--eol >= tag && apr_isspace(*eol))
                    *eol = '\0';
                if ((mime_info.body = get_body(buffer, &len, tag, *map)) < 0) {
                    ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00685)
                                  "Syntax error in type map, no end tag '%s'"
                                  "found in %s for Body: content.",
                                  tag, r->filename);
                     break;
                }
                mime_info.bytes = len;
                mime_info.file_name = apr_filepath_name_get(rr->filename);
            }
        }
        else {
            if (*mime_info.file_name && has_content) {
                void *new_var = apr_array_push(neg->avail_vars);

                memcpy(new_var, (void *) &mime_info, sizeof(var_rec));
            }

            clean_var_rec(&mime_info);
            has_content = 0;
        }
    } while (hstate != header_eof);

    if (map_)
        apr_file_close(map_);

    set_vlist_validator(r, rr);

    return OK;
}

/* Sort function used by read_types_multi. */
static int variantsortf(var_rec *a, var_rec *b)
{
    /* First key is the source quality, sort in descending order. */

    /* XXX: note that we currently implement no method of setting the
     * source quality for multiviews variants, so we are always comparing
     * 1.0 to 1.0 for now
     */
    if (a->source_quality < b->source_quality)
        return 1;
    if (a->source_quality > b->source_quality)
        return -1;

    /* Second key is the variant name */
    return strcmp(a->file_name, b->file_name);
}

/*****************************************************************
 *
 * Same as read_type_map, except we use a filtered directory listing
 * as the map...
 */

static int read_types_multi(negotiation_state *neg)
{
    request_rec *r = neg->r;

    char *filp;
    int prefix_len;
    apr_dir_t *dirp;
    apr_finfo_t dirent;
    apr_status_t status;
    struct var_rec mime_info;
    struct accept_rec accept_info;
    void *new_var;
    int anymatch = 0;

    clean_var_rec(&mime_info);

    if (r->proxyreq || !r->filename
                    || !ap_os_is_path_absolute(neg->pool, r->filename)) {
        return DECLINED;
    }

    /* Only absolute paths here */
    if (!(filp = strrchr(r->filename, '/'))) {
        return DECLINED;
    }
    ++filp;
    prefix_len = strlen(filp);

    if ((status = apr_dir_open(&dirp, neg->dir_name,
                               neg->pool)) != APR_SUCCESS) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(00686)
                    "cannot read directory for multi: %s", neg->dir_name);
        return HTTP_FORBIDDEN;
    }

    while (apr_dir_read(&dirent, APR_FINFO_DIRENT, dirp) == APR_SUCCESS) {
        apr_array_header_t *exception_list;
        request_rec *sub_req;

        /* Do we have a match? */
#ifdef CASE_BLIND_FILESYSTEM
        if (strncasecmp(dirent.name, filp, prefix_len)) {
#else
        if (strncmp(dirent.name, filp, prefix_len)) {
#endif
            continue;
        }
        if (dirent.name[prefix_len] != '.') {
            continue;
        }

        /* Don't negotiate directories and other unusual files
         * Really shouldn't see anything but DIR/LNK/REG here,
         * and we aught to discover if the LNK was interesting.
         *
         * Of course, this only helps platforms that capture the
         * the filetype in apr_dir_read(), which most can once
         * they are optimized with some magic [it's known to the
         * dirent, not associated to the inode, on most FS's.]
         */
        if ((dirent.valid & APR_FINFO_TYPE) && (dirent.filetype == APR_DIR))
            continue;

        /* Ok, something's here.  Maybe nothing useful.  Remember that
         * we tried, if we completely fail, so we can reject the request!
         */
        anymatch = 1;

        /* See if it's something which we have access to, and which
         * has a known type and encoding.
         */
        sub_req = ap_sub_req_lookup_dirent(&dirent, r, AP_SUBREQ_MERGE_ARGS,
                                           NULL);

        /* Double check, we still don't multi-resolve non-ordinary files
         */
        if (sub_req->finfo.filetype != APR_REG) {
            /* XXX sub req not destroyed -- may be a bug/unintentional ? */
            continue;
        }

        /* If it has a handler, we'll pretend it's a CGI script,
         * since that's a good indication of the sort of thing it
         * might be doing.
         */
        if (sub_req->handler && !sub_req->content_type) {
            ap_set_content_type(sub_req, CGI_MAGIC_TYPE);
        }

        /*
         * mod_mime will _always_ provide us the base name in the
         * ap-mime-exception-list, if it processed anything.  If
         * this list is empty, give up immediately, there was
         * nothing interesting.  For example, looking at the files
         * readme.txt and readme.foo, we will throw away .foo if
         * it's an insignificant file (e.g. did not identify a
         * language, charset, encoding, content type or handler,)
         */
        exception_list =
            (apr_array_header_t *)apr_table_get(sub_req->notes,
                                                "ap-mime-exceptions-list");

        if (!exception_list) {
            ap_destroy_sub_req(sub_req);
            continue;
        }

        /* Each unregonized bit better match our base name, in sequence.
         * A test of index.html.foo will match index.foo or index.html.foo,
         * but it will never transpose the segments and allow index.foo.html
         * because that would introduce too much CPU consumption.  Better that
         * we don't attempt a many-to-many match here.
         */
        {
            int nexcept = exception_list->nelts;
            char **cur_except = (char**)exception_list->elts;
            char *segstart = filp, *segend, saveend;

            while (*segstart && nexcept) {
                if (!(segend = strchr(segstart, '.')))
                    segend = strchr(segstart, '\0');
                saveend = *segend;
                *segend = '\0';

#ifdef CASE_BLIND_FILESYSTEM
                if (strcasecmp(segstart, *cur_except) == 0) {
#else
                if (strcmp(segstart, *cur_except) == 0) {
#endif
                    --nexcept;
                    ++cur_except;
                }

                if (!saveend)
                    break;

                *segend = saveend;
                segstart = segend + 1;
            }

            if (nexcept) {
                /* Something you don't know is, something you don't know...
                 */
                ap_destroy_sub_req(sub_req);
                continue;
            }
        }

        /*
         * If we failed the subrequest, or don't
         * know what we are serving, then continue.
         */
        if (sub_req->status != HTTP_OK || (!sub_req->content_type)) {
            ap_destroy_sub_req(sub_req);
            continue;
        }

        /* If it's a map file, we use that instead of the map
         * we're building...
         */
        if (((sub_req->content_type) &&
             !strcmp(sub_req->content_type, MAP_FILE_MAGIC_TYPE)) ||
            ((sub_req->handler) &&
             !strcmp(sub_req->handler, "type-map"))) {

            apr_dir_close(dirp);
            neg->avail_vars->nelts = 0;
            if (sub_req->status != HTTP_OK) {
                return sub_req->status;
            }
            return read_type_map(NULL, neg, sub_req);
        }

        /* Have reasonable variant --- gather notes. */

        mime_info.sub_req = sub_req;
        mime_info.file_name = apr_pstrdup(neg->pool, dirent.name);
        if (sub_req->content_encoding) {
            mime_info.content_encoding = sub_req->content_encoding;
        }
        if (sub_req->content_languages) {
            mime_info.content_languages = sub_req->content_languages;
        }

        get_entry(neg->pool, &accept_info, sub_req->content_type);
        set_mime_fields(&mime_info, &accept_info);

        new_var = apr_array_push(neg->avail_vars);
        memcpy(new_var, (void *) &mime_info, sizeof(var_rec));

        neg->count_multiviews_variants++;

        clean_var_rec(&mime_info);
    }

    apr_dir_close(dirp);

    /* We found some file names that matched.  None could be served.
     * Rather than fall out to autoindex or some other mapper, this
     * request must die.
     */
    if (anymatch && !neg->avail_vars->nelts) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00687)
                      "Negotiation: discovered file(s) matching request: %s"
                      " (None could be negotiated).",
                      r->filename);
        return HTTP_NOT_FOUND;
    }

    set_vlist_validator(r, r);

    /* Sort the variants into a canonical order.  The negotiation
     * result sometimes depends on the order of the variants.  By
     * sorting the variants into a canonical order, rather than using
     * the order in which readdir() happens to return them, we ensure
     * that the negotiation result will be consistent over filesystem
     * backup/restores and over all mirror sites.
     */

    qsort((void *) neg->avail_vars->elts, neg->avail_vars->nelts,
          sizeof(var_rec), (int (*)(const void *, const void *)) variantsortf);

    return OK;
}


/*****************************************************************
 * And now for the code you've been waiting for... actually
 * finding a match to the client's requirements.
 */

/* Matching MIME types ... the star/star and foo/star commenting conventions
 * are implemented here.  (You know what I mean by star/star, but just
 * try mentioning those three characters in a C comment).  Using strcmp()
 * is legit, because everything has already been smashed to lowercase.
 *
 * Note also that if we get an exact match on the media type, we update
 * level_matched for use in level_cmp below...
 *
 * We also give a value for mime_stars, which is used later. It should
 * be 1 for star/star, 2 for type/star and 3 for type/subtype.
 */

static int mime_match(accept_rec *accept_r, var_rec *avail)
{
    const char *accept_type = accept_r->name;
    const char *avail_type = avail->mime_type;
    int len = strlen(accept_type);

    if ((len == 1 && accept_type[0] == '*')
            || (len == 3 && !strncmp(accept_type, "*/*", 3))) {
        /* Anything matches star or star/star */
        if (avail->mime_stars < 1) {
            avail->mime_stars = 1;
        }
        return 1;
    }
    else if (len > 2 && accept_type[len - 2] == '/'
                     && accept_type[len - 1] == '*'
                     && !strncmp(accept_type, avail_type, len - 2)
                     && avail_type[len - 2] == '/') {
        /* Any subtype matches for type/star */
        if (avail->mime_stars < 2) {
            avail->mime_stars = 2;
        }
        return 1;
    }
    else if (!strcmp(accept_type, avail_type)
             || (!strcmp(accept_type, "text/html")
                 && (!strcmp(avail_type, INCLUDES_MAGIC_TYPE)
                     || !strcmp(avail_type, INCLUDES_MAGIC_TYPE3)))) {
        if (accept_r->level >= avail->level) {
            avail->level_matched = avail->level;
            avail->mime_stars = 3;
            return 1;
        }
    }

    return OK;
}

/* This code implements a piece of the tie-breaking algorithm between
 * variants of equal quality.  This piece is the treatment of variants
 * of the same base media type, but different levels.  What we want to
 * return is the variant at the highest level that the client explicitly
 * claimed to accept.
 *
 * If all the variants available are at a higher level than that, or if
 * the client didn't say anything specific about this media type at all
 * and these variants just got in on a wildcard, we prefer the lowest
 * level, on grounds that that's the one that the client is least likely
 * to choke on.
 *
 * (This is all motivated by treatment of levels in HTML --- we only
 * want to give level 3 to browsers that explicitly ask for it; browsers
 * that don't, including HTTP/0.9 browsers that only get the implicit
 * "Accept: * / *" [space added to avoid confusing cpp --- no, that
 * syntax doesn't really work] should get HTML2 if available).
 *
 * (Note that this code only comes into play when we are choosing among
 * variants of equal quality, where the draft standard gives us a fair
 * bit of leeway about what to do.  It ain't specified by the standard;
 * rather, it is a choice made by this server about what to do in cases
 * where the standard does not specify a unique course of action).
 */

static int level_cmp(var_rec *var1, var_rec *var2)
{
    /* Levels are only comparable between matching media types */

    if (var1->is_pseudo_html && !var2->is_pseudo_html) {
        return 0;
    }

    if (!var1->is_pseudo_html && strcmp(var1->mime_type, var2->mime_type)) {
        return 0;
    }
    /* The result of the above if statements is that, if we get to
     * here, both variants have the same mime_type or both are
     * pseudo-html.
     */

    /* Take highest level that matched, if either did match. */

    if (var1->level_matched > var2->level_matched) {
        return 1;
    }
    if (var1->level_matched < var2->level_matched) {
        return -1;
    }

    /* Neither matched.  Take lowest level, if there's a difference. */

    if (var1->level < var2->level) {
        return 1;
    }
    if (var1->level > var2->level) {
        return -1;
    }

    /* Tied */

    return 0;
}

/* Finding languages.  The main entry point is set_language_quality()
 * which is called for each variant. It sets two elements in the
 * variant record:
 *    language_quality  - the 'q' value of the 'best' matching language
 *                        from Accept-Language: header (HTTP/1.1)
 *    lang_index    -     Non-negotiated language priority, using
 *                        position of language on the Accept-Language:
 *                        header, if present, else LanguagePriority
 *                        directive order.
 *
 * When we do the variant checking for best variant, we use language
 * quality first, and if a tie, language_index next (this only applies
 * when _not_ using the RVSA/1.0 algorithm). If using the RVSA/1.0
 * algorithm, lang_index is never used.
 *
 * set_language_quality() calls find_lang_index() and find_default_index()
 * to set lang_index.
 */

static int find_lang_index(apr_array_header_t *accept_langs, char *lang)
{
    const char **alang;
    int i;

    if (!lang || !accept_langs) {
        return -1;
    }

    alang = (const char **) accept_langs->elts;

    for (i = 0; i < accept_langs->nelts; ++i) {
        if (!strncmp(lang, *alang, strlen(*alang))) {
            return i;
        }
        alang += (accept_langs->elt_size / sizeof(char*));
    }

    return -1;
}

/* set_default_lang_quality() sets the quality we apply to variants
 * which have no language assigned to them. If none of the variants
 * have a language, we are not negotiating on language, so all are
 * acceptable, and we set the default q value to 1.0. However if
 * some of the variants have languages, we set this default to 0.0001.
 * The value of this default will be applied to all variants with
 * no explicit language -- which will have the effect of making them
 * acceptable, but only if no variants with an explicit language
 * are acceptable. The default q value set here is assigned to variants
 * with no language type in set_language_quality().
 *
 * Note that if using the RVSA/1.0 algorithm, we don't use this
 * fiddle.
 */

static void set_default_lang_quality(negotiation_state *neg)
{
    var_rec *avail_recs = (var_rec *) neg->avail_vars->elts;
    int j;

    if (!neg->dont_fiddle_headers) {
        for (j = 0; j < neg->avail_vars->nelts; ++j) {
            var_rec *variant = &avail_recs[j];
            if (variant->content_languages &&
                variant->content_languages->nelts) {
                neg->default_lang_quality = 0.0001f;
                return;
            }
        }
    }

    neg->default_lang_quality = 1.0f;
}

/* Set the language_quality value in the variant record. Also
 * assigns lang_index for ForceLanguagePriority.
 *
 * To find the language_quality value, we look for the 'q' value
 * of the 'best' matching language on the Accept-Language
 * header. The 'best' match is the language on Accept-Language
 * header which matches the language of this variant either fully,
 * or as far as the prefix marker (-). If two or more languages
 * match, use the longest string from the Accept-Language header
 * (see HTTP/1.1 [14.4])
 *
 * When a variant has multiple languages, we find the 'best'
 * match for each variant language tag as above, then select the
 * one with the highest q value. Because both the accept-header
 * and variant can have multiple languages, we now have a hairy
 * loop-within-a-loop here.
 *
 * If the variant has no language and we have no Accept-Language
 * items, leave the quality at 1.0 and return.
 *
 * If the variant has no language, we use the default as set by
 * set_default_lang_quality() (1.0 if we are not negotiating on
 * language, 0.001 if we are).
 *
 * Following the setting of the language quality, we drop through to
 * set the old 'lang_index'. This is set based on either the order
 * of the languages on the Accept-Language header, or the
 * order on the LanguagePriority directive. This is only used
 * in the negotiation if the language qualities tie.
 */

static void set_language_quality(negotiation_state *neg, var_rec *variant)
{
    int forcepriority = neg->conf->forcelangpriority;
    if (forcepriority == FLP_UNDEF) {
        forcepriority = FLP_DEFAULT;
    }

    if (!variant->content_languages || !variant->content_languages->nelts) {
        /* This variant has no content-language, so use the default
         * quality factor for variants with no content-language
         * (previously set by set_default_lang_quality()).
         * Leave the factor alone (it remains at 1.0) when we may not fiddle
         * with the headers.
         */
        if (!neg->dont_fiddle_headers) {
            variant->lang_quality = neg->default_lang_quality;
        }
        if (!neg->accept_langs) {
            return;             /* no accept-language header */
        }
        return;
    }
    else {
        /* Variant has one (or more) languages.  Look for the best
         * match. We do this by going through each language on the
         * variant description looking for a match on the
         * Accept-Language header. The best match is the longest
         * matching language on the header. The final result is the
         * best q value from all the languages on the variant
         * description.
         */

        if (!neg->accept_langs) {
            /* no accept-language header makes the variant indefinite */
            variant->definite = 0;
        }
        else {    /* There is an accept-language with 0 or more items */
            accept_rec *accs = (accept_rec *) neg->accept_langs->elts;
            accept_rec *best = NULL, *star = NULL;
            accept_rec *bestthistag;
            char *lang, *p;
            float fiddle_q = 0.0f;
            int any_match_on_star = 0;
            int i, j;
            apr_size_t alen, longest_lang_range_len;

            for (j = 0; j < variant->content_languages->nelts; ++j) {
                p = NULL;
                bestthistag = NULL;
                longest_lang_range_len = 0;

                /* lang is the variant's language-tag, which is the one
                 * we are allowed to use the prefix of in HTTP/1.1
                 */
                lang = ((char **) (variant->content_languages->elts))[j];

                /* now find the best (i.e. longest) matching
                 * Accept-Language header language. We put the best match
                 * for this tag in bestthistag. We cannot update the
                 * overall best (based on q value) because the best match
                 * for this tag is the longest language item on the accept
                 * header, not necessarily the highest q.
                 */
                for (i = 0; i < neg->accept_langs->nelts; ++i) {
                    if (!strcmp(accs[i].name, "*")) {
                        if (!star) {
                            star = &accs[i];
                        }
                        continue;
                    }
                    /* Find language. We match if either the variant
                     * language tag exactly matches the language range
                     * from the accept header, or a prefix of the variant
                     * language tag up to a '-' character matches the
                     * whole of the language range in the Accept-Language
                     * header.  Note that HTTP/1.x allows any number of
                     * '-' characters in a tag or range, currently only
                     * tags with zero or one '-' characters are defined
                     * for general use (see rfc1766).
                     *
                     * We only use language range in the Accept-Language
                     * header the best match for the variant language tag
                     * if it is longer than the previous best match.
                     */

                    alen = strlen(accs[i].name);

                    if ((strlen(lang) >= alen) &&
                        !strncmp(lang, accs[i].name, alen) &&
                        ((lang[alen] == 0) || (lang[alen] == '-')) ) {

                        if (alen > longest_lang_range_len) {
                            longest_lang_range_len = alen;
                            bestthistag = &accs[i];
                        }
                    }

                    if (!bestthistag && !neg->dont_fiddle_headers) {
                        /* The next bit is a fiddle. Some browsers might
                         * be configured to send more specific language
                         * ranges than desirable. For example, an
                         * Accept-Language of en-US should never match
                         * variants with languages en or en-GB. But US
                         * English speakers might pick en-US as their
                         * language choice.  So this fiddle checks if the
                         * language range has a prefix, and if so, it
                         * matches variants which match that prefix with a
                         * priority of 0.001. So a request for en-US would
                         * match variants of types en and en-GB, but at
                         * much lower priority than matches of en-US
                         * directly, or of any other language listed on
                         * the Accept-Language header. Note that this
                         * fiddle does not handle multi-level prefixes.
                         */
                        if ((p = strchr(accs[i].name, '-'))) {
                            int plen = p - accs[i].name;

                            if (!strncmp(lang, accs[i].name, plen)) {
                                fiddle_q = 0.001f;
                            }
                        }
                    }
                }
                /* Finished looking at Accept-Language headers, the best
                 * (longest) match is in bestthistag, or NULL if no match
                 */
                if (!best ||
                    (bestthistag && bestthistag->quality > best->quality)) {
                    best = bestthistag;
                }

                /* See if the tag matches on a * in the Accept-Language
                 * header. If so, record this fact for later use
                 */
                if (!bestthistag && star) {
                    any_match_on_star = 1;
                }
            }

            /* If one of the language tags of the variant matched on *, we
             * need to see if its q is better than that of any non-* match
             * on any other tag of the variant.  If so the * match takes
             * precedence and the overall match is not definite.
             */
            if ( any_match_on_star &&
                ((best && star->quality > best->quality) ||
                 (!best)) ) {
                best = star;
                variant->definite = 0;
            }

            variant->lang_quality = best ? best->quality : fiddle_q;
        }
    }

    /* Handle the ForceDefaultLanguage overrides, based on the best match
     * to LanguagePriority order.  The best match is the lowest index of
     * any LanguagePriority match.
     */
    if (((forcepriority & FLP_PREFER)
             && (variant->lang_index < 0))
     || ((forcepriority & FLP_FALLBACK)
             && !variant->lang_quality))
    {
        int bestidx = -1;
        int j;

        for (j = 0; j < variant->content_languages->nelts; ++j)
        {
            /* lang is the variant's language-tag, which is the one
             * we are allowed to use the prefix of in HTTP/1.1
             */
            char *lang = ((char **) (variant->content_languages->elts))[j];
            int idx;

            /* If we wish to fallback or
             * we use our own LanguagePriority index.
             */
            idx = find_lang_index(neg->conf->language_priority, lang);
            if ((idx >= 0) && ((bestidx == -1) || (idx < bestidx))) {
                bestidx = idx;
            }
        }

        if (bestidx >= 0) {
            if (variant->lang_quality) {
                if (forcepriority & FLP_PREFER) {
                    variant->lang_index = bestidx;
                }
            }
            else {
                if (forcepriority & FLP_FALLBACK) {
                    variant->lang_index = bestidx;
                    variant->lang_quality = .0001f;
                    variant->definite = 0;
                }
            }
        }
    }
}

/* Determining the content length --- if the map didn't tell us,
 * we have to do a stat() and remember for next time.
 */

static apr_off_t find_content_length(negotiation_state *neg, var_rec *variant)
{
    apr_finfo_t statb;

    if (variant->bytes < 0) {
        if (   variant->sub_req
            && (variant->sub_req->finfo.valid & APR_FINFO_SIZE)) {
            variant->bytes = variant->sub_req->finfo.size;
        }
        else {
            char *fullname = ap_make_full_path(neg->pool, neg->dir_name,
                                               variant->file_name);

            if (apr_stat(&statb, fullname,
                         APR_FINFO_SIZE, neg->pool) == APR_SUCCESS) {
                variant->bytes = statb.size;
            }
        }
    }

    return variant->bytes;
}

/* For a given variant, find the best matching Accept: header
 * and assign the Accept: header's quality value to the
 * mime_type_quality field of the variant, for later use in
 * determining the best matching variant.
 */

static void set_accept_quality(negotiation_state *neg, var_rec *variant)
{
    int i;
    accept_rec *accept_recs;
    float q = 0.0f;
    int q_definite = 1;

    /* if no Accept: header, leave quality alone (will
     * remain at the default value of 1)
     *
     * XXX: This if is currently never true because of the effect of
     * maybe_add_default_accepts().
     */
    if (!neg->accepts) {
        if (variant->mime_type && *variant->mime_type)
            variant->definite = 0;
        return;
    }

    accept_recs = (accept_rec *) neg->accepts->elts;

    /*
     * Go through each of the ranges on the Accept: header,
     * looking for the 'best' match with this variant's
     * content-type. We use the best match's quality
     * value (from the Accept: header) for this variant's
     * mime_type_quality field.
     *
     * The best match is determined like this:
     *    type/type is better than type/ * is better than * / *
     *    if match is type/type, use the level mime param if available
     */
    for (i = 0; i < neg->accepts->nelts; ++i) {

        accept_rec *type = &accept_recs[i];
        int prev_mime_stars;

        prev_mime_stars = variant->mime_stars;

        if (!mime_match(type, variant)) {
            continue;           /* didn't match the content type at all */
        }
        else {
            /* did match - see if there were less or more stars than
             * in previous match
             */
            if (prev_mime_stars == variant->mime_stars) {
                continue;       /* more stars => not as good a match */
            }
        }

        /* If we are allowed to mess with the q-values
         * and have no explicit q= parameters in the accept header,
         * make wildcards very low, so we have a low chance
         * of ending up with them if there's something better.
         */

        if (!neg->dont_fiddle_headers && !neg->accept_q &&
            variant->mime_stars == 1) {
            q = 0.01f;
        }
        else if (!neg->dont_fiddle_headers && !neg->accept_q &&
                 variant->mime_stars == 2) {
            q = 0.02f;
        }
        else {
            q = type->quality;
        }

        q_definite = (variant->mime_stars == 3);
    }
    variant->mime_type_quality = q;
    variant->definite = variant->definite && q_definite;

}

/* For a given variant, find the 'q' value of the charset given
 * on the Accept-Charset line. If no charsets are listed,
 * assume value of '1'.
 */
static void set_charset_quality(negotiation_state *neg, var_rec *variant)
{
    int i;
    accept_rec *accept_recs;
    const char *charset = variant->content_charset;
    accept_rec *star = NULL;

    /* if no Accept-Charset: header, leave quality alone (will
     * remain at the default value of 1)
     */
    if (!neg->accept_charsets) {
        if (charset && *charset)
            variant->definite = 0;
        return;
    }

    accept_recs = (accept_rec *) neg->accept_charsets->elts;

    if (charset == NULL || !*charset) {
        /* Charset of variant not known */

        /* if not a text / * type, leave quality alone */
        if (!(!strncmp(variant->mime_type, "text/", 5)
              || !strcmp(variant->mime_type, INCLUDES_MAGIC_TYPE)
              || !strcmp(variant->mime_type, INCLUDES_MAGIC_TYPE3)
              ))
            return;

        /* Don't go guessing if we are in strict header mode,
         * e.g. when running the rvsa, as any guess won't be reflected
         * in the variant list or content-location headers.
         */
        if (neg->dont_fiddle_headers)
            return;

        charset = "iso-8859-1"; /* The default charset for HTTP text types */
    }

    /*
     * Go through each of the items on the Accept-Charset header,
     * looking for a match with this variant's charset. If none
     * match, charset is unacceptable, so set quality to 0.
     */
    for (i = 0; i < neg->accept_charsets->nelts; ++i) {

        accept_rec *type = &accept_recs[i];

        if (!strcmp(type->name, charset)) {
            variant->charset_quality = type->quality;
            return;
        }
        else if (strcmp(type->name, "*") == 0) {
            star = type;
        }
    }
    /* No explicit match */
    if (star) {
        variant->charset_quality = star->quality;
        variant->definite = 0;
        return;
    }
    /* If this variant is in charset iso-8859-1, the default is 1.0 */
    if (strcmp(charset, "iso-8859-1") == 0) {
        variant->charset_quality = 1.0f;
    }
    else {
        variant->charset_quality = 0.0f;
    }
}


/* is_identity_encoding is included for back-compat, but does anyone
 * use 7bit, 8bin or binary in their var files??
 */

static int is_identity_encoding(const char *enc)
{
    return (!enc || !enc[0] || !strcmp(enc, "7bit") || !strcmp(enc, "8bit")
            || !strcmp(enc, "binary"));
}

/*
 * set_encoding_quality determines whether the encoding for a particular
 * variant is acceptable for the user-agent.
 *
 * The rules for encoding are that if the user-agent does not supply
 * any Accept-Encoding header, then all encodings are allowed but a
 * variant with no encoding should be preferred.
 * If there is an empty Accept-Encoding header, then no encodings are
 * acceptable. If there is a non-empty Accept-Encoding header, then
 * any of the listed encodings are acceptable, as well as no encoding
 * unless the "identity" encoding is specifically excluded.
 */
static void set_encoding_quality(negotiation_state *neg, var_rec *variant)
{
    accept_rec *accept_recs;
    const char *enc = variant->content_encoding;
    accept_rec *star = NULL;
    float value_if_not_found = 0.0f;
    int i;

    if (!neg->accept_encodings) {
        /* We had no Accept-Encoding header, assume that all
         * encodings are acceptable with a low quality,
         * but we prefer no encoding if available.
         */
        if (!enc || is_identity_encoding(enc))
            variant->encoding_quality = 1.0f;
        else
            variant->encoding_quality = 0.5f;

        return;
    }

    if (!enc || is_identity_encoding(enc)) {
        enc = "identity";
        value_if_not_found = 0.0001f;
    }

    accept_recs = (accept_rec *) neg->accept_encodings->elts;

    /* Go through each of the encodings on the Accept-Encoding: header,
     * looking for a match with our encoding. x- prefixes are ignored.
     */
    if (enc[0] == 'x' && enc[1] == '-') {
        enc += 2;
    }
    for (i = 0; i < neg->accept_encodings->nelts; ++i) {

        char *name = accept_recs[i].name;

        if (name[0] == 'x' && name[1] == '-') {
            name += 2;
        }

        if (!strcmp(name, enc)) {
            variant->encoding_quality = accept_recs[i].quality;
            return;
        }

        if (strcmp(name, "*") == 0) {
            star = &accept_recs[i];
        }

    }
    /* No explicit match */
    if (star) {
        variant->encoding_quality = star->quality;
        return;
    }